A semi-automated material exploration scheme to predict the solubilities of tetraphenylporphyrin derivatives.

Acceleration of material discovery has been tackled by informatics and laboratory automation. Here we show a semi-automated material exploration scheme to modelize the solubility of tetraphenylporphyrin derivatives. The scheme involved the following steps: definition of a practical chemical search space, prioritization of molecules in the space using an extended algorithm for submodular function maximization without requiring biased variable selection or pre-existing data, synthesis & automated measurement, and machine-learning model estimation. The optimal evaluation order selected using the algorithm covered several similar molecules (32% of all targeted molecules, whereas that obtained by random sampling and uncertainty sampling was ~7% and ~4%, respectively) with a small number of evaluations (10 molecules: 0.13% of all targeted molecules). The derived binary classification models predicted 'good solvents' with an accuracy >0.8. Overall, we confirmed the effectivity of the proposed semi-automated scheme in early-stage material search projects for accelerating a wider range of material research.

Three-Staged Surgical Strategy as a Combined Approach for Multilevel Cervical Pyogenic Spondylodiscitis.

Cervical pyogenic spondylodiscitis is rare but can lead to severe clinical problems that often require aggressive surgical treatment for neurological deterioration and life-threatening conditions. Although combined surgical procedures are often utilized to treat multilevel cervical regions, there is a clinical debate regarding the appropriate order and timing of surgeries using the anterior and posterior approaches. Here, we report a case of severe multilevel cervical pyogenic spondylodiscitis treated using a three-staged surgical strategy consisting of cervical laminectomy, posterior fixation, and anterior corpectomy and fusion with an autologous long bone graft; the outcome was quite favorable. Our report demonstrates the safety and usefulness of three-staged surgery in the multilevel cervical region, especially under urgent situations.

[A case of dural arteriovenous fistula at the craniocervical junction, which spinal MRI findings reveals increased intensity signal in Th3-medullary cone].

A 60-year-old woman had transient weakness of the legs and urinary retention for six weeks. She presented with a gait disorder and was admitted to the hospital. She showed symptoms of paraplegia, tingling in the lower extremities, dysuria. She underwent an MRI, and T2-weighted images showed an enlargement of the thoracolumbar spinal cord and high intensity signal from Th3 to the medullary cone, and a contrast-enhanced T1-weighted image showed abnormal vessels anterior to the spine cord. Cervical and spinal angiography documented a dural arteriovenous fistula at the craniocervical junction that was fed by the right vertebral artery and the right ascending pharyngeal arteries and drained into the perimedullary veins. Surgical therapy improved her symptoms and MRI images. Craniocervical junction DAVF with thoracic-medullary cones lesion is rare.

A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations.

We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density; and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786 432 cores for a 50.3 × 10(6)-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16 661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques are employed for efficiently calculating the long-range exact exchange correction and excited-state forces. The NAQMD trajectories are analyzed to extract the rates of various excitonic processes, which are then used in KMC simulation to study the dynamics of the global exciton flow network. This has allowed the study of large-scale photoexcitation dynamics in 6400-atom amorphous molecular solid, reaching the experimental time scales.

Enhanced charge transfer by phenyl groups at a rubrene/C60 interface.

Exciton dynamics at an interface between an electron donor, rubrene, and a C(60) acceptor is studied by nonadiabatic quantum molecular dynamics simulation. Simulation results reveal an essential role of the phenyl groups in rubrene in increasing the charge-transfer rate by an order-of-magnitude. The atomistic mechanism of the enhanced charge transfer is found to be the amplification of aromatic breathing modes by the phenyl groups, which causes large fluctuations of electronic excitation energies. These findings provide insight into molecular structure design for efficient solar cells, while explaining recent experimental observations.