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The zero-energy variance principle can be exploited in variational quantum eigensolvers for solving general eigenstates but its capacity for obtaining a specified eigenstate, such as ground state, is limited as all eigenstates are of zero energy variance. We propose a variance-based variational quantum eigensolver for solving the ground state by searching in an enlarged space of wavefunction and Hamiltonian. With a mutual variance-Hamiltonian optimization procedure, the Hamiltonian is iteratively updated to guild the state towards to the ground state of the target Hamiltonian by minimizing the energy variance in each iteration. We demonstrate the performance and properties of the algorithm with numeral simulations. Our work suggests an avenue for utilizing guided Hamiltonian in hybrid quantum-classical algorithms.

The original variational quantum eigensolver (VQE) typically minimizes energy with hybrid quantum-classical optimization that aims to find the ground state. Here, we propose a VQE based on minimizing energy variance and call it the variance-VQE, which treats the ground state and excited states on the same footing, since an arbitrary eigenstate for a Hamiltonian should have zero energy variance. We demonstrate the properties of the variance-VQE for solving a set of excited states in quantum chemistry problems. Remarkably, we show that optimization of a combination of energy and variance may be more efficient to find low-energy excited states than those of minimizing energy or variance alone. We further reveal that the optimization can be boosted with stochastic gradient descent by Hamiltonian sampling, which uses only a few terms of the Hamiltonian and thus significantly reduces the quantum resource for evaluating variance and its gradients.

Background Curcumin (Cur), derived from Curcuma species, exhibits anti‐inflammatory, antioxidant, and anticancer effects. Although Cur has some beneficial effects on asthma, its clinical application is limited by its low bioavailability. Tetrahydrocurcumin (THC), the major active metabolite of Cur, has multiple biological functions, similarly to Cur, and importantly, it showed enhanced bioavailability in tissues and plasma. However, the effect of THC on asthma has not been reported. Objective The current study sought to investigate the efficacy of dietary THC on allergic asthma compared to that of Cur in an animal model. Methods The anti‐inflammatory effects of Cur and THC were evaluated in an ovalbumin‐induced asthmatic mouse model. The nasal symptoms, pathological alterations of the lung tissues, oxidants and antioxidants, cytokine production, T cell subsets, and Th2‐related signalling pathway activity were assessed. Results Both THC and Cur had beneficial effects on asthmatic mice with regard to nasal symptoms, pathological changes (eosinophils and mucus hyper‐production), oxidative stress (malondialdehyde), cytokine production (IL‐13), Th17 and cytotoxic T cell subsets, and Th2 signalling pathway (IL‐4Rα‐Jak1‐STAT6 and Jagged1/Jagged2‐Notch1/Notch2 axis) activity. THC was more effective than Cur in suppressing tissue eosinophilia, mucus production, and IL‐4Rα/Jak1/STAT6 pathway activity. Furthermore, only THC inhibited peripheral eosinophil levels, Th2 cytokines (IL‐4 and IL‐5), and Th2 cell subsets and enhanced an antioxidant enzyme (glutathione). Conclusion and Clinical Relevance The above results demonstrated for the first time that THC was superior to Cur in modulating allergic asthmatic phenotypes, especially attenuating the Th2 response. THC might be a potentially effective agent for asthma treatment.

[Purpose] To investigate the effects of transcutaneous electrical nerve stimulation (TENS) on pain in patients with spinal cord injury. [Subjects and Methods] Fifty-two spinal cord injury patients with central pain were randomly allocated into two groups TENS and control with 26 subjects per group. The patients in TENS and control groups were treated with TENS and sham TENS for 20 min (three times a week) for 12 consecutive weeks, respectively. The two group’s pain was assessed using visual analog scale (VAS) and the McGill Pain Questionnaire (including pain rating index-total, pain rating index-affective, pain rating index-sensory, present pain intensity, and number of words chosen) before and after the treatment. [Results] After the intervention, we found significant differences in VAS, pain rating index-total, pain rating index-affective, pain rating index-sensory, present pain intensity, and number of words chosen between the TENS group and the control group. [Conclusion] Our results suggest that TENS effectively decreases pain in patients with spinal cord injury.

Background: Low back pain affects approximately 80% of people at some stage in their lives. Exercise therapy is the most widely used nonsurgical intervention for low back pain in practice guidelines. Whole body vibration exercise is becoming increasingly popular for relieving musculoskeletal pain and improving health-related quality of life. However, the efficacy of whole body vibration exercise for low back pain is not without dispute. This study aims to estimate the effect of whole body vibration exercise for chronic low back pain. Methods/Design: We will conduct a prospective, single-blind, randomized controlled trial of 120 patients with chronic low back pain. Patients will be randomly assigned into an intervention group and a control group. The intervention group will participate in whole body vibration exercise twice a week for 3 months. The control group will receive general exercise twice a week for 3 months. Primary outcome measures will be the visual analog scale for pain, the Oswestry Disability Index and adverse events. The secondary outcome measures will include muscle strength and endurance of spine, trunk proprioception, transversus abdominis activation capacity, and quality of life. We will conduct intention-to-treat analysis if any participants withdraw from the trial. Discussion: Important features of this study include the randomization procedures, single-blind, large sample size, and a standardized protocol for whole body vibration in chronic low back pain. This study aims to determine whether whole body vibration exercise produces more beneficial effects than general exercise for chronic low back pain. Therefore, our results will be useful for patients with chronic low back pain as well as for medical staff and health-care decision makers. Trial registration: Chinese Clinical Trial Registry: ChiCTR-TRC-13003708.

Background and purpose An increasing interest in the potential benefits of cognitive motor interference (CMI) for stroke has recently been observed, but the efficacy of CMI for gait and balance is controversial. A systematic review and meta-analysis of randomized controlled trials was performed to estimate the effect of CMI on gait and balance in patients with stroke. Methods Articles in Medline, EMBASE, the Cochrane Library, Web of Science, CINAHL, PEDro and the China Biology Medicine disc were searched from 1970 to July 2014. Only randomized controlled trials examining the effects of CMI for patients with stroke were included, and no language restrictions were applied. Main outcome measures included gait and balance function. Results A total of 15 studies composed of 395 participants met the inclusion criteria, and 13 studies of 363 participants were used as data sources for the meta-analysis. Pooling revealed that CMI was superior to the control group for gait speed [mean difference (MD) 0.19 m/s, 95% confidence interval (CI) (0.06, 0.31), P = 0.003], stride length [MD 12.53 cm, 95% CI (4.07, 20.99), P = 0.004], cadence [MD 10.44 steps/min, 95% CI (4.17, 16.71), P = 0.001], centre of pressure sway area [MD −1.05, 95% CI (−1.85, −0.26), P = 0.01] and Berg balance scale [MD 2.87, 95% CI (0.54, 5.21), P = 0.02] in the short term. Conclusion Cognitive motor interference is effective for improving gait and balance function for stroke in the short term. However, only little evidence supports assumptions regarding CMI's long-term benefits.

In the mol­ecule of the title compound, C15H13ClN2O4, the pyrimidine and benzene rings form a dihedral angle of 69.3 (3)°. No π–π stacking inter­actions are observed in the crystal structure.

The mol­ecule of the title compound, C5H2Cl3N, is essentially planar. In the crystal structure, mol­ecules are stacked along the short a axis and form a layer structure parallel to the (\overline{1}02) plane. No π–π stacking inter­actions or hydrogen bonds are observed.