Improving the exchange and correlation potential in density-functional approximations through constraints.

We review and expand on our work to impose constraints on the effective Kohn-Sham (KS) potential of local and semi-local density-functional approximations. Constraining the minimisation of the approximate total energy density-functional invariably leads to an optimised effective potential (OEP) equation, the solution of which yields the KS potential. We review briefly our previous work on this and demonstrate with numerous examples that despite the well-known mathematical issues of the OEP with finite basis sets, our OEP equations are numerically robust. We demonstrate that appropriately constraining the 'screening charge' which corresponds to the Hartree, exchange and correlation potential not only corrects its asymptotic behaviour but also allows the exchange and correlation potential to exhibit a non-zero derivative discontinuity, a feature of the exact KS potential that is necessary for the accurate prediction of band-gaps in solids but very hard to capture with semi-local approximations.

Systematic review of neurotrophic tropomyosin-related kinase inhibition as a tumor-agnostic management strategy.

Aim: To conduct a systematic review and meta-analysis feasibility of clinical, quality of life and economic evidence for neurotrophic tropomyosin-related receptor tyrosine kinases (NTRK) inhibitors in patients with NTRK gene fusion-positive tumors. Materials & methods: Databases were searched for studies on NTRK inhibitors in adult and pediatric patients. Results: 27 publications reported clinical data for seven interventions. Efficacy/safety data were available for two interventions only. Four trials each reported data for larotrectinib and entrectinib with pooled analyses reporting objective response rates of 75% (95% CI: 61-85) and 57.4% (43.2-70.8), respectively. No publications reported economic or quality of life evidence. Conclusion: Preliminary data demonstrate that NTRK inhibitors are well tolerated and show impressive clinical benefit; corroboration of existing studies and real-world data are required.

Patient selection for anti-PD-1/PD-L1 therapy in advanced non-small-cell lung cancer: implications for clinical practice.

Immune checkpoint inhibitors targeting PD-1 or PD-L1 represent a standard treatment option for patients with advanced non-small-cell lung cancer. However, a substantial proportion of patients will not benefit from these treatments, and robust biomarkers are required to help clinicians select patients who are most likely to benefit. Here, we discuss the available evidence on the utility of clinical characteristics in the selection of patients with advanced non-small-cell lung cancer as potential candidates for single-agent anti-PD-1/PD-L1 therapy, and provide practical guidance to clinicians on identifying those patients who are most likely to benefit. Recommendations on the use of immune checkpoint inhibitor in clinically challenging populations are also provided.

Extracellular Matrix from Whole Porcine Heart Decellularization for Cardiac Tissue Engineering.

Decellularization of whole porcine hearts followed by recellularization with fully differentiated cells made from patient-specific human induced pluripotent stem cells (iPSCs) may provide the ultimate solution for patients with heart failure. Decellularization is the process of completely disrupting all cells and removing the cellular components (e.g., antigenic proteins, lipids, DNA) from organic tissue, leaving only the extracellular matrix (ECM). The decellularization of porcine hearts can be accomplished in 24 h and results in 98% DNA removal with only 6 h of detergent exposure. Automatically controlling the pressure during decellularization reduces the detergent exposure time while still completely removing immunogenic cell debris.

Spin Relaxation in GaAs: Importance of Electron-Electron Interactions.

We study spin relaxation in n-type bulk GaAs, due to the Dyakonov-Perel mechanism, using ensemble Monte Carlo methods. Our results confirm that spin relaxation time increases with the electronic density in the regime of moderate electronic concentrations and high temperature. We show that the electron-electron scattering in the non-degenerate regime significantly slows down spin relaxation. This result supports predictions by Glazov and Ivchenko. Most importantly, our findings highlight the importance of many-body interactions for spin dynamics: we show that only by properly taking into account electron-electron interactions within the simulations, results for the spin relaxation time-with respect to both electron density and temperature-will reach good quantitative agreement with corresponding experimental data. Our calculations contain no fitting parameters.

Postactivation potentiation of force is independent of h-reflex excitability.

UNLABELLED: The contractile history of muscle can potentiate electrically evoked force production. A link to voluntary force production, related in part to an increase in reflex excitability, has been suggested. PURPOSE: Our purpose was to quantify the effect of postactivation potentiation on voluntary force production and spinal H-reflex excitability during explosive plantar flexion actions. METHODS: Plantar flexor twitch torque, soleus H-reflex amplitudes, and the rate of force development of explosive plantar flexion were measured before and after 4 separate conditioning trials (3 x 5 s maximal contractions). RESULTS: Twitch torque and rate of force production during voluntary explosive plantar flexion were significantly increased (P < .05) while H-reflex amplitudes remained unchanged. Although twitch torque was significantly higher after conditioning, leading to a small increase in the rate of voluntary force production, this was unrelated to changes in reflex excitability. CONCLUSION: We conclude that postactivation potentiation may result in a minor increase in the rate of voluntary isometric force production that is unrelated to neural excitability.

The application of postactivation potentiation to elite sport.

Recently there has been considerable interest and research into the functional significance of postactivation potentiation (PAP) on sport performance. The interest has evolved around the potential for enhancing acute performance or the long-term training effect, typically in the form of complex training. Complex training usually involves performing a weight-training exercise with high loads before executing a plyometric exercise with similar biomechanical demands. Despite a considerable amount of research in the past 10 years it would seem there is still much research to be done to fully determine whether PAP has a functional role and, if so, how to best exploit it. It is clear from the research that there are many factors that need to be considered when attempting to apply PAP to an athlete. It is possible that a well-conceived sport-specific warm-up might be as or more effective in enhancing acute performance and easier to apply in a practical setting. In addition, despite its current popularity, there has not been 1 study that has effectively examined the efficacy of complex training and whether it has any advantage over other forms of training that combine weight training and plyometrics but not in the same training session.