Materials discovery with extreme properties via reinforcement learning-guided combinatorial chemistry.

The goal of most materials discovery is to discover materials that are superior to those currently known. Fundamentally, this is close to extrapolation, which is a weak point for most machine learning models that learn the probability distribution of data. Herein, we develop reinforcement learning-guided combinatorial chemistry, which is a rule-based molecular designer driven by trained policy for selecting subsequent molecular fragments to get a target molecule. Since our model has the potential to generate all possible molecular structures that can be obtained from combinations of molecular fragments, unknown molecules with superior properties can be discovered. We theoretically and empirically demonstrate that our model is more suitable for discovering better compounds than probability distribution-learning models. In an experiment aimed at discovering molecules that hit seven extreme target properties, our model discovered 1315 of all target-hitting molecules and 7629 of five target-hitting molecules out of 100 000 trials, whereas the probability distribution-learning models failed. Moreover, it has been confirmed that every molecule generated under the binding rules of molecular fragments is 100% chemically valid. To illustrate the performance in actual problems, we also demonstrate that our models work well on two practical applications: discovering protein docking molecules and HIV inhibitors.

Flavor characteristics of garlic fish cakes using electronic nose and tongue analyses.

This study investigated the utility of garlic powder as a functional ingredient. The aim was to develop fish cakes with improved functionality and sensory preference based on the antioxidant activity and quality characteristics. Increasing amounts of garlic powder in the prepared fish cakes were associated with increasing total polyphenol and flavonoid contents, 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazolin-6-sulfonic acid) (ABTS+) radical scavenging activity, and reducing power. Furthermore, electronic tongue and electronic nose analyses showed an increased the intensity of umami and sourness and increased the levels of volatile compounds. The lowest trimethylamine peak corresponded to the highest amount of garlic powder. Sensory evaluation indicated that 3% garlic powder had the highest score for all criteria. Fishy odor decreased as the proportion of garlic powder increased. These findings suggest that the addition of 3% garlic powder improves quality characteristics, sensory preference, and antioxidant activity of fish cakes.

Quality characteristics and antioxidant activity of meringue Jeung-pyun with different amounts of cacao bean husk.

In this study, we aimed to investigate the quality characteristics, antioxidant activity, and sensory traits of meringue Jeung-pyun with different amounts of cacao bean husk powder. Based on our analyses, high cacao bean husk content resulted in an increase in certain Jeung-pyun qualities, such as the L values, b values, hardness, gumminess, and number of pores, whereas the moisture content, pH, pore size, adhesiveness, cohesiveness, and chewiness significantly decreased. Electronic tongue analysis showed that the intensity of sourness, saltiness, and umami increased with the amount of cacao bean husk added. For the sensory characteristics, C6 demonstrated the highest ranking for all test items. Furthermore, it was found that the addition of cacao bean husks increased the antioxidant activity of the Jeung-pyun (p < 0.001). Therefore, these results suggest that Jeung-pyun produced with a mixing ratio of C6 has excellent qualities, antioxidant activities, and sensory characteristics.

Effects of Panicum miliaceum L. extract on adipogenic transcription factors and fatty acid accumulation in 3T3-L1 adipocytes.

The dietary intake of whole grains is known to reduce the incidence of chronic diseases such as obesity, diabetes, cardiovascular disease, and cancer. To investigate whether there are anti-adipogenic activities in various Korean cereals, we assessed water extracts of nine cereals. The results showed that treatment of 3T3-L1 adipocytes with Sorghum bicolor L. Moench, Setaria italica Beauvois, or Panicum miliaceum L. extract significantly inhibited adipocyte differentiation, as determined by measuring oil red-O staining, triglyceride accumulation, and glycerol 3-phosphate dehydrogenase activity. Among the nine cereals, P. miliaceum L. showed the highest anti-adipogenic activity. The effects of P. miliaceum L. on mRNA expression of peroxisome proliferator-activated receptor-γ, sterol regulatory element-binding protein 1, and the CCAAT/enhancer binding protein-α were evaluated, revealing that the extract significantly decreased the expression of these genes in a dose-dependent manner. Moreover, P. miliaceum L. extract changed the ratio of monounsaturated fatty acids to saturated fatty acids in adipocytes, which is related to biological activity and cell characteristics. These results suggest that some cereals efficiently suppress adipogenesis in 3T3-L1 adipocytes. In particular, the effect of P. miliaceum L. on adipocyte differentiation is associated with the downregulation of adipogenic genes and fatty acid accumulation in adipocytes.

Validity and reproducibility of a food frequency questionnaire to assess dietary nutrients for prevention and management of metabolic syndrome in Korea.

Little data exists on metabolic syndrome (MetS) related with intake, especially for the South Korean. The purpose of this study was to develop and evaluate a food frequency questionnaire (FFQ) for nutritional assessment in the population with MetS in South Korea. Randomly selected female participants, mean age 21.9 years (n = 38) were invited to answer the FFQ twice (FFQ1 and FFQ2) over a nine-month interval and to complete twelve-day diet records (DR) during the months between in South Korea. The correlation coefficients for nutrient intake between FFQ1 and FFQ2 varied from 0.253 (niacin) to 0.573 (cholesterol), and the energy intake-adjusted correlation coefficients ranged from 0.187 for protein to 0.662 for iron. The energy intake-adjusted and de-attenuated correlation coefficients for comparison of FFQ1 and the DRs ranged between 0.277 (vitamin B1) and 0.768 (fiber), and between 0.229 (zinc) and 0.859 (fat) for comparison of DRs with FFQ2. The percentages of study subjects classified into the same quartiles in both the DRs and FFQ1 ranged from 15.8% (vitamin B(6)) to 47.4% (calcium), and for the same quartiles in DRs and FFQ2 from 13.2% (vitamin B(1)) to 44.7% (potassium). The FFQ has reasonably good validity and reproducibility. Further research is needed for an assessment of reproducibility and validation of present FFQ in the subjects with MetS.

Prevalence of cryptosporidiosis among the villagers and domestic animals in several rural areas of Korea.

The present study was undertaken to investigate the infection status of Cryptosporidium parvum in the villagers and the reservoir hosts in several rural areas in Korea. A total 5,262 fecal samples were collected from the inhabitants residing at Gangwon-do, Chungcheongbuk-do, Jeollanam-do, and Gyeongsangnam-do between the dates of September, 2001 to June, 2002. In addition, 1,453 fecal samples were collected from livestock reared in Gokseong-gun, Jeollanam-do and Chungju-si, Chungcheongbuk-do. All the fecal smears were prepared by formalin-ether sedimentation, and examined by light microscopy after modified acid-fast staining. The overall positive rate of human cryptosporidiosis was 3.3%. Gokseong-gun, Jeollanam-do showed a 8.2% positive rate and appeared as the highest endemic area among the surveyed areas. Haman-gun, Gyeongsangnam-do showed a 0.4% positive rate and was the lowest endemic area. The positive rate of livestock infection in Gokseong-gun, Jeollanam-do was 94%, which was more than ten times higher than that of Chungju-si, Chungcheongbuk-do (9.3%). From these results, it was revealed that cryptosporidiosis was an endemic disease in some rural areas of Korea, and the livestock could be an important source of human infection.