Enzymatic Production and Biological Activities of Cellobio-oligosaccharides from Lignocellulose

Cellulose is the most abundant biopolymer in nature and is the major component of lignocellulosic biomass. It has potential to produce not only glucose but value¨Cadded products such as cellobiose and oligosaccharides. Typically, enzymatic hydrolysis of cellulose produces glucose and a small amount of cellobiose. Modification of cellulase solutions altered ratio of glucose to cellobiose produced. The addition of glucose oxidase, gluconolactone, or gluconic acid significantly increased the amount of cellobiose remaining at the end of cellulose hydrolysis. Addition of glucose oxidase resulted in cellobiose being 23.7% of the product sugars from pure cellulose and 14.1% from ligonocellulose (sugarcane bagasse). The presence of gluconolactone in the reaction mixture increased cellobiose to 31.3% of the sugars from cellulose and 15.8% from bagasse. The presence of gluconic acid changed the cellobiose to 21.9% of the sugars from cellulose and 13.2% from bagasse. In order to produce cellobio-oligosaccharides, a dextransucrase from Leuconostoc mesenteroides B-512FMCM was employed to catalyze the transglycosylation reaction between cellobiose and sucrose. The major cellobio-oligosaccharides were the trisaccharides, ¦Á-D-glucopyranosyl-(1¡ú2)-cellobiose and ¦Á-D-glucopyranosyl-(1¡ú6)-cellobiose. Cellobio-oligosaccharides have valuable functional properties as potential antifungal and anticariogenic agents, and an ¦Á-glucosidase inhibitor

Compatibility between Teachers Beliefs and Those of Students with Varying Proficiency Levels Concerning Korean Language Learning

This study aims to explore language learning beliefs of Korean language learners from three different levels of proficiency and then compare their beliefs with those of language teachers who are native speakers of Korean. A total of 126 participants (ninety nine students and 27 teachers) were asked to fill out a questionnaire, the Beliefs about Language Learning Inventory (BALLI). The findings show that the students from the three levels of proficiency hold many similar beliefs on language learning, but they also hold some different beliefs. The analysis of an ANOVA and a Post-hoc revealed that the mean differences for certain items were statistically significant among the three groups. Also, the findings revealed that the students and the teachers maintain different beliefs, and the analysis of a t-test for the two groups showed that some differences between the two groups are statistically significant. These findings yield some points for teachers to contemplate with a view to promoting students motivation and language learning

Low Temperature Synthesis of Hexagonal Shaped α

This study demonstrates the low temperature synthesis of α-Al2O3 by solvothermal method using gibbsite alumina precursor in 1, 4-butanediol solvent according to various pH conditions. In acidic solution, an orthorhombic boehmite (AlOOH) structure was obtained after solvothermal reaction. A significant result in this study was that the solvothermally synthesized alumina in pH=9 at 300 °C for 36 h represented a rhombohedral α-Al2O3 structure hexagonal shaped with about 1.5~2.0 μm of particle size. Otherwise, the α-Al2O3 structure was rather changed to the mixture of a boehmite and α-Al2O3 structures above pH=11. In the case of α-Al2O3 synthesized at pH=9, the specific surface area was 26.18 m2/g, and the particles that were stable in acidic solution resulted in 61.80 mV of zeta potential

The experience of unmarried mothers raising their children in residential facilities: a phenomenological qualitative study

Background : Birth outside of marriage has been gradually increasing in Korea. However, social perception of unmarried mothers is still negative, and a number of them are not accepted by their family. Therefore, the Korean government has implemented a policy to provide financial aid and communal residence to unmarried mothers who cannot raise children with their family, or afford residence. Unmarried young mothers who rely on this government policy have low economic independence and social adaptation skills. Additionally, they have a high chance of encountering numerous challenges in raising children due to their living conditions in residential facilities and social prejudice. This study was conducted to gain an in-depth understanding of the lived experience of unmarried mothers raising children in residential facilities. Methods : Data were collected through in-depth interviews with nine unmarried mothers living in residential facilities with their children. An interpretative phenomenological analysis was conducted to analyze the data. Results : The findings revealed that unmarried mothers struggled with various difficulties given the limitations of living in the facility, but attempted to navigate their uncertain future with the determination to be good mothers. Three main themes and eight sub-themes emerged: (1) adaptation to the identity of “unmarried mother”, (2) willingly undertaking the heavy burden of childrearing, (3) indispensable but insufficient supports from facilities. Participants had childrearing responsibilities, and tried to be good mothers for their children while struggling to adapt to their new identities. However, their self-doubt as a “good mother” and the absence of the child's father made them feel sorry for their child. Their daily experiences raising children and simultaneously preparing for their own independence were exhausting. The supports from the facilities were helpful but unsatisfactory and led to various psychosocial difficulties such as anxiety, depression, fear, guilty, and anger in unmarried mothers. Conclusions : Besides information and resources for parenting and independence, active approaches are needed to improve the psychological stability of unmarried mothers raising their children in facilities, and sustain a long-term socioeconomic support system. Thoughtful services tailored to mothers and children are also needed, instead of standardized services.This work was supported by the National Research Foundation of Korea (NRF) under grant by the Korea government (MSIT) (No. NRF-2019R1A2B5B01070519)

Nostalgia : concerto for violin and orchestra

Musi

Predictive Growth Modeling of Listeria monocytogenes in Rice Balls and Its Risk Assessment

This study aimed to investigate the growth of Listeria monocytogenes in rice balls and to conduct its microbial risk assessment based on the Korean dietary pattern. Each tuna or ham rice ball was mixed with mayonnaise, soy sauce, or gochujang, a Korean traditional fermented red peeper paste, which was artificially contaminated with L. monocytogenes and then stored at 7°C–25°C to assess bacterial growth. Growth data were analyzed using three primary models (the Huang, Baranyi, and Gompertz models), and the growth pattern was found to fit well to the Baranyi model based on the following five statistical criteria: root mean square error (0.38–0.56), Akaike’s information criterion (−51.55–−26.99), coefficient of determination (0.72–0.97), bias factor (0.97–1.01), and accuracy factor (1.06–1.18). The effects of temperature on bacterial growth rate and lag time were evaluated using the square root model. The minimum growth temperature for L. monocytogenes in tuna or ham rice balls was the lowest when they were mixed with mayonnaise (−9.44°C or −15.37°C, respectively). Risk assessment using FDA-iRISK showed that tuna or ham rice balls mixed with gochujang exhibited the highest microbial risk among all the rice balls tested, regardless of the storage temperature. Tuna or ham rice balls mixed with gochujang had the highest disability-adjusted life years per year (0.015) followed by ham rice balls mixed with soy sauce (0.011–0.015) or mayonnaise (0.006–0.015) and then tuna rice balls mixed with soy sauce (0.006–0.008) or mayonnaise (<0.001). In conclusion, our results, determined using predictive growth models, allow the assessment of potential risk ranking associated with the consumption of rice balls contaminated with L. monocytogenes based on the number of illnesses experienced per serving and the disease burden

Antidiabetic, Anticholesterol, and Antioxidant Activity of <i>Gryllus</i><i>bimaculatus</i> Fermented by <i>Bacillus</i> and <i>Lactobacillus</i> Strains

In this study, functionality of Gryllusbimaculatus (GB) fermented by Bacillus and Lactobacillus strain was investigated. GB was fermented by each of the following strains: probiotic Bacillus amyloliquefaciens MKSK-J1 (SKGB), probiotic Lactobacillus plantarum MKHA15 (HAGB), Bacillus amyloliquefaciens MKSE (SEGB), and Lactobacillus plantarum KCTC 3103 (LPGB). Fermentation was carried out at 35 °C for 24 h. In HAGB, complete inhibition of α-glucosidase and 3-hydroxy-methyl glutaryl-coenzyme A (HMG-CoA) reductase occurred (101.94% and 120.89%, respectively), and superoxide dismutase (SOD)-like activity (IC50) was significantly low (22.37 mg/mL). After in vitro digestion, SOD-like activity was the highest in HAGB (21.18%). In SKGB, reducing power (EC50) was significantly low (0.29 mg/mL). After in vitro digestion, the reducing was also highest in SKGB (86.06%). Fermentation enhanced the bioactivity of GB; in particular, MKHA15 was found to have great potential as a starter in the production of fermented GB, as it would offer multi-health functions, including antidiabetic, anticholesterol, and antioxidant activity