Exploration of new chemical materials using black-box optimization with the D-wave quantum annealer

In materials informatics, searching for chemical materials with desired properties is challenging due to the vastness of the chemical space. Moreover, the high cost of evaluating properties necessitates a search with a few clues. In practice, there is also a demand for proposing compositions that are easily synthesizable. In the real world, such as in the exploration of chemical materials, it is common to encounter problems targeting black-box objective functions where formalizing the objective function in explicit form is challenging, and the evaluation cost is high. In recent research, a Bayesian optimization method has been proposed to formulate the quadratic unconstrained binary optimization (QUBO) problem as a surrogate model for black-box objective functions with discrete variables. Regarding this method, studies have been conducted using the D-Wave quantum annealer to optimize the acquisition function, which is based on the surrogate model and determines the next exploration point for the black-box objective function. In this paper, we address optimizing a black-box objective function containing discrete variables in the context of actual chemical material exploration. In this optimization problem, we demonstrate results obtaining parameters of the acquisition function by sampling from a probability distribution with variance can explore the solution space more extensively than in the case of no variance. As a result, we found combinations of substituents in compositions with the desired properties, which could only be discovered when we set an appropriate variance.Comment: 14pages, 4figures, 4table

Aflatoxins in Rice Artificially Contaminated with Aflatoxin-producing Aspergillus flavus under Natural Storage in Japan

Aflatoxin (AFT) contamination is frequent in foods grown in tropical regions, including rice. Although AFTs are generally not found in temperate-region foods, global warming has affected typical temperate-region climates, potentially permitting the contamination of foods with AFT-producing Aspergillus flavus (A. flavus). Here we investigated the AFT production in rice during storage under natural climate conditions in Japan. We examined AFTs in brown rice and rough rice artificially contaminated with A. flavus for 1 year in Japan, and we subjected AFTs in white rice to the same treatment in airtight containers and examined the samples in warm and cold seasons, simulating the storage of white rice in general households. In the brown rice, AFTs increased after 2 months (March) and peaked after 9 months (October). The AFT contamination in the rough rice was minimal. After the polishing and cooking of the brown rice, AFTs were undetectable. In the white rice stored in airtight containers, AFTs increased after 1 month (August) and peaked after 2 months (September). Minimal AFTs were detected in the cold season. Thus, AFT contamination in rice may occur in temperate regions following A. flavus contamination. The storage of rice as rough rice could provide be useful for avoiding AFT contamination

Right thoracic curvature in the normal spine

<p>Abstract</p> <p>Background</p> <p>Trunk asymmetry and vertebral rotation, at times observed in the normal spine, resemble the characteristics of adolescent idiopathic scoliosis (AIS). Right thoracic curvature has also been reported in the normal spine. If it is determined that the features of right thoracic side curvature in the normal spine are the same as those observed in AIS, these findings might provide a basis for elucidating the etiology of this condition. For this reason, we investigated right thoracic curvature in the normal spine.</p> <p>Methods</p> <p>For normal spinal measurements, 1,200 patients who underwent a posteroanterior chest radiographs were evaluated. These consisted of 400 children (ages 4-9), 400 adolescents (ages 10-19) and 400 adults (ages 20-29), with each group comprised of both genders. The exclusion criteria were obvious chest and spinal diseases. As side curvature is minimal in normal spines and the range at which curvature is measured is difficult to ascertain, first the typical curvature range in scoliosis patients was determined and then the Cobb angle in normal spines was measured using the same range as the scoliosis curve, from T5 to T12. Right thoracic curvature was given a positive value. The curve pattern was organized in each collective three groups: neutral (from -1 degree to 1 degree), right (> +1 degree), and left (< -1 degree).</p> <p>Results</p> <p>In child group, Cobb angle in left was 120, in neutral was 125 and in right was 155. In adolescent group, Cobb angle in left was 70, in neutral was 114 and in right was 216. In adult group, Cobb angle in left was 46, in neutral was 102 and in right was 252. The curvature pattern shifts to the right side in the adolescent group (p < 0.01) and in adult group (p < 0.001) compared to the child group. There was no significant difference in curvature pattern between adolescent and adult group.</p> <p>Conclusions</p> <p>Based on standing chest radiographic measurements, a right thoracic curvature was observed in normal spines after adolescence.</p

Geodesy reference points within Syowa Station, Antarctica, and their local geodetic ties

In order to study geodynamics in relation to atmospheric, oceanographic and glaciological interactions on a global scale, adequate distribution of precise geodesy stations over the Earth is important. Syowa Station (69.0°S , 39.6°E ), Antarctica, serves as one of the observatories in the Southern Hemisphere. This report briefly summarizes the location coordinates of the geodetic sensors, and chronology of related activity as of 2005, based on standardized format sheets for each sensor monument. Exchange of these formatted sheets among Antarctic stations will give us a data base for reviewing and archiving geodetic activity in Antarctica. Local geodetic ties among their monument marks are updated from the results given by M. Kanao et al. (J. Geod. Soc. Jpn., 41, 357, 1995), including later surveying with improved accuracy

Nonlinear Elasticity of Single Collapsed Polyelectrolytes

Nonlinear elastic responses of short and stiff polyelectrolytes are investigated by dynamic simulations on a single molecule level. When a polyelectrolyte condensate undergoes a mechanical unfolding, two types of force-extension curves, i.e., a force plateau and a stick-release pattern, are observed depending on the strength of the electrostatic interaction. We provide a physical interpretation of such force-extension behavior in terms of intramolecular structures of the condensates. We also describe a charge distribution of condensed counterions onto a highly stretched polyelectrolyte, which clarifies a formation of one-dimensional strongly correlated liquid at large Coulomb coupling regime where a stick-release pattern is observed. These findings may provide significant insights into the relationship between a molecular elasticity and a molecular mechanism of like-charge attractions observed in a wide range of charged biopolymer systems.Comment: 5pages, 5figure

Capacidade de união de resinas adesivas à dentina afetada e infectada por cárie

Hybridized dentin permits dental treatments that were previously impossible with conventional techniques, opening new frontiers in modern adhesive dentistry. We have investigated the adhesive property of current bonding systems to caries-infected dentin by a microtensile bond strength test (µTBS) and transmission electron microscopy (TEM), and suggested that bonding resin could infiltrate into caries-infected dentin partially to embed carious bacteria within hybrid layers. We have named this concept of caries control as modified sealed restoration (MSR). On the other hand, Kuraray Medical Inc. (Tokyo, Japan) has developed an antibacterial adhesive system (ABF, now marketed in USA as Protect Bond). So as to evaluate the effectiveness of ABF on root caries control, we have examine the microtensile bond strengths (µTBS) of ABF to normal versus carious root dentin and the interfacial morphology by a scanning electron microscopy (SEM). ABF could form the hybrid-like structures by infiltrating into the surfaces of the root carious dentin, and the mean value of µTBS of ABF to root carious dentin was 23.0 MPa. These results suggested that MSR combined with ABF might be an advantageous minimal invasive therapy for root caries.As técnicas adesivas permitiram inovações nos tratamentos restauradores da atualidade. Este estudo investigou a qualidade de união de diferentes sistemas adesivos ao substrato dentinário afetado e infectado por cárie, através de testes de microtração e microscopia eletrônica de transmissão e varredura (MET). Os resultados sugerem que a resina adesiva pôde infiltrar na dentina infectada e envolver as bactérias na camada híbrida. Esse conceito de controle da cárie foi denominado de "Restauração-Selante Modificada" (RSM). Por outro lado, a empresa Kuraray Med. Inc .(Japão) desenvolveu um sistema adesivo com propriedades anti-bacterianas (ABF), o qual é comercializado nos EUA como Protect Bond. Para avaliar a efetividade do sistema ABF sobre cáries radiculares, empregou-se testes de resistência adesiva e análise por microscopia eletrônica. O sistema ABF foi capaz de formar uma estrutura interfacial semelhante à camada híbrida, através da infiltração na superfície da dentina cariada radicular e os valores de resistência de união foram em média de 23 MPa. Os achados sugerem que a combinação da técnica RSM com o sistema ABF parece ser uma alternativa para o emprego da terapia de mínima invasão em cáries radiculares

The first year of Antarctic VLBI observations

We are undertaking a series of geodetic VLBI observations between the Syowa Station 11-m antenna in Antarctica, and the 26-m antennas in Hobart Tasmania and Hartebeesthoek South Africa. These observations are the beginning of our campaign to monitor the motion and stability of the Antarctic plate. We describe here the results of the first year\u27s observations made during the southern summer and winter of 1998. Two mutually incompatible recording systems, K4 and S2, are used. The Mitaka FX Correlator was used to correlate these data. By using software called CALC3/MSOLV, the mean position of the antenna\u27s geodetic reference point was found to be X=1766194.152±0.006m, Y=1460410.923±0.005m and Z=- 5932273.329±0.015m at the epoch of 1998.9 in the International Terrestrial Reference Frame 2000 (ITRF2000) system. From a comparison with measurements made with other space geodetic techniques we estimate that our results have typical uncertainties of no more than 2 to 3cm in each coordinate