Public Perception Towards Drug Abuse in South Korea: The Effects of Overconfidence and Affirmation.

OBJECTIVE: The abuse of prescription drugs and over-the-counter medicines has been a major issue addressed as a serious public health problem worldwide. This study explored factors contributing to substance abuse in Korea by examining the status of substance abuse among Korean adults and evaluating their knowledge, attitudes, and intentions toward substance abuse. METHODS: Data were collected online from a sample of participants 19 years old or older from May 20 to June 1, 2020 (n=1,020). The survey consisted of questions on demographics, perceptions of drug risk, motives for drug use, and attitudes toward drug addiction treatment. Principal component and multiple logistic regression analyses were used to explore the factors contributing to the perception of drug abuse. RESULTS: In the multivariate regression analysis, overconfidence in handling drug usage, acceptance of addictive substances, and affirmation of public support for drug abuse were associated with opioid abuse (Nagelkerke R2=0.486), and additionally affirmation of legal cannabis usage and motivation to use diet pills were associated with diet pill abuse (Nagelkerke R2=0.569). CONCLUSION: The findings of this study suggest that the actual situation of substance abuse among Korean adults increases awareness of and attitudes toward drug use related to substance abuse.

Effectiveness of the Korean-Patient Placement Criteria for Alcohol Use Disorders: A Prospective Exploratory Study.

OBJECTIVE: Various patient placement criteria (PPC) have been developed to address alcohol use disorder (AUD), which has a high relapse rate and imposes substantial socioeconomic costs. Although research has shown PPC to be an effective tool, evidence supporting the Korean-PPC (K-PPC) is insufficient. This paper investigated whether treatment matching with the K-PPC was effective, based on variables related to AUD. METHODS: In total, 524 participants were evaluated using the 6 dimensions of the K-PPC and levels of care (LoC) were recommended based on the results. Participants whose treatment matched with the recommended LoC were classified into the matched group, and those whose treatment did not match were classified into the mismatched group. Subsequently, treatment was planned according to the determined LoC, and a total of 3 follow-up evaluations were conducted at 1 month, 3 months, and 6 months. RESULTS: There was no significant difference in the follow-up rate between the K-PPC matched group and the mismatched group. Of the variables measured by the 6 dimensions of the K-PPC, alcohol-related variables, depression, insight, and biomedical outcomes showed the most significant results (especially alcohol-related variables) from the baseline evaluation to the 6-month follow-up. In addition, the average adherence to the treatment program in the 6-month period was found to be higher in the matched group than in the mismatched group. CONCLUSION: The K-PPC could be effective for placing patients and providing treatment by matching patient characteristics. Enhancing treatment program retention can also have a positive effect on clinical outcomes.

IRE1 is implicated in protein synthesis regulation under ER stress conditions in plants.

The unfolded protein response (UPR) is a crucial cellular mechanism for maintaining protein folding homeostasis during endoplasmic reticulum (ER) stress. In this study, the role of IRE1, a key component of the UPR, was investigated in protein translation regulation under ER stress conditions in Arabidopsis. We discovered that the loss of IRE1A and IRE1B leads to diminished protein translation, indicating a significant role for IRE1 in this process. However, this regulation was not solely dependent on the interaction with bZIP60, a key transcription factor in the UPR. Interestingly, while chemical chaperones TUDCA and PBA effectively alleviated the translation inhibition observed in ire1a ire1b mutants, this effect was more pronounced than the mitigation observed from suppressing GCN2 expression or introducing a non-phosphorylatable eIF2α variant. Additionally, the kinase and ribonuclease activities of IRE1B were demonstrated to be crucial for plant adaptation and protein synthesis regulation under ER stress conditions. Overall, this study not only highlights the complex regulatory mechanisms of IRE1 in plant ER stress responses but also provides insights into its multifaceted roles in protein translation regulation.

Evaluating the factor structure and measurement invariance of the 20-item short version of the UPPS-P Impulsive Behavior Scale across multiple countries, languages, and gender identities.

The UPPS-P Impulsive Behavior Model and the various psychometric instruments developed and validated based on this model are well established in clinical and research settings. However, evidence regarding the psychometric validity, reliability, and equivalence across multiple countries of residence, languages, or gender identities, including gender-diverse individuals, is lacking to date. Using data from the International Sex Survey (N = 82,243), confirmatory factor analyses and measurement invariance analyses were performed on the preestablished five-factor structure of the 20-item short version of the UPPS-P Impulsive Behavior Scale to examine whether (a) psychometric validity and reliability and (b) psychometric equivalence hold across 34 country-of-residence-related, 22 language-related, and three gender-identity-related groups. The results of the present study extend the latter psychometric instrument's well-established relevance to 26 countries, 13 languages, and three gender identities. Most notably, psychometric validity and reliability were evidenced across nine novel translations included in the present study (i.e., Croatian, English, German, Hebrew, Korean, Macedonian, Polish, Portuguese-Portugal, and Spanish-Latin American) and psychometric equivalence was evidenced across all three gender identities included in the present study (i.e., women, men, and gender-diverse individuals).

Inner/Outer Side Chain Engineering of Non-Fullerene Acceptors for Efficient Large-Area Organic Solar Modules Based on Non-Halogenated Solution Processing in Air.

Achieving efficient and large-area organic solar modules via non-halogenated solution processing is vital for the commercialization yet challenging. The primary hurdle is the conservation of the ideal film-formation kinetics and bulk-heterojunction (BHJ) morphology of large-area organic solar cells (OSCs). A cutting-edge non-fullerene acceptor (NFA), Y6, shows efficient power conversion efficiencies (PCEs) when processed with toxic halogenated solvents, but exhibits poor solubility in non-halogenated solvents, resulting in suboptimal morphology. Therefore, in this study, the impact of modifying the inner and outer side-chains of Y6 on OSC performance is investigated. The study reveals that blending a polymer donor, PM6, with one of the modified NFAs, namely N-HD, achieved an impressive PCE of 18.3% on a small-area OSC. This modified NFA displays improved solubility in o-xylene at room temperature, which facilitated the formation of a favorable BHJ morphology. A large-area (55 cm2) sub-module delivered an impressive PCE of 12.2% based on N-HD using o-xylene under ambient conditions. These findings underscore the significant impact of the modified Y6 derivatives on structural arrangements and film processing over a large-area module at room temperature. Consequently, these results are poised to deepen the comprehension of the scaling challenges encountered in OSCs and may contribute to their commercialization.

Why Do People Watch Pornography? Cross-Cultural Validation of the Pornography Use Motivations Scale (PUMS) and Its Short Form (PUMS-8).

Motivations for pornography use may vary across gender identities, sexual orientations, and geographical regions, warranting examination to promote individual and public health. The aims of this study were to validate the Pornography Use Motivations Scale (PUMS) in a diverse, multicultural sample, and develop a short form (PUMS-8) that can assess a wide range of pornography use motivations. Using data from 42 countries (N = 75,117; Mage = 32.07; SDage = 12.37), enabled us to thoroughly evaluate the dimensionality, validity, and reliability of the Pornography Use Motivations Scale (PUMS), leading to the development of the more concise PUMS-8 short scale. Additionally, language-, nationality-, gender-, and sexual-orientation-based measurement invariance tests were conducted to test the comparability across groups. Both the PUMS and the PUMS-8 assess eight pornography use motivations, and both demonstrated excellent psychometric properties. Sexual Pleasure emerged as the most frequent motivation for pornography use across countries, genders, and sexual orientations, while differences were observed concerning other motivations (e.g. self-exploration was more prevalent among gender-diverse individuals than men or women). The motivational background of pornography use showed high similarity in the examined countries. Both the PUMS and the PUMS-8 are reliable and valid measurement tools to assess different types of motivations for pornography use across countries, genders, and sexual orientations. Both scales are recommended for use in research and clinical settings.

The short version of the Sexual Distress Scale (SDS-3): Measurement invariance across countries, gender identities, and sexual orientations.

Background: The three-item Sexual Distress Scale (SDS-3) has been frequently used to assess distress related to sexuality in public health surveys and research on sexual wellbeing. However, its psychometric properties and measurement invariance across cultural, gender and sexual subgroups have not yet been examined. This multinational study aimed to validate the SDS-3 and test its psychometric properties, including measurement invariance across language, country, gender identity, and sexual orientation groups. Methods: We used global survey data from 82,243 individuals (Mean age=32.39 years; 40.3 % men, 57.0 % women, 2.8 % non-binary, and 0.6 % other genders) participating in the International Sexual Survey (ISS; https://internationalsexsurvey.org/) across 42 countries and 26 languages. Participants completed the SDS-3, as well as questions regarding sociodemographic characteristics, including gender identity and sexual orientation. Results: Confirmatory factor analysis (CFA) supported a unidimensional factor structure for the SDS-3, and multi-group CFA (MGCFA) suggested that this factor structure was invariant across countries, languages, gender identities, and sexual orientations. Cronbach's α for the unidimensional score was 0.83 (range between 0.76 and 0.89), and McDonald's ω was 0.84 (range between 0.76 and 0.90). Participants who did not experience sexual problems had significantly lower SDS-3 total scores (M = 2.99; SD=2.54) compared to those who reported sexual problems (M = 5.60; SD=3.00), with a large effect size (Cohen's d = 1.01 [95 % CI=-1.03, -0.98]; p < 0.001). Conclusion: The SDS-3 has a unidimensional factor structure and appears to be valid and reliable for measuring sexual distress among individuals from different countries, gender identities, and sexual orientations.

An empirical study on social network analysis for small residential communities in Gangwon State, South Korea.

Social Network Analysis (SNA) provides a dynamic framework for examining interactions and connections within networks, elucidating how these relationships impact behaviors and outcomes. This study targeted small residential communities in Gangwon State, South Korea, to explore network formation theories and derive strategies for enhancing health promotion services in rural communities. Conducted in 12 small residential areas, the survey led to a network categorization model distinguishing networks as formal, informal, or non-existent. Key findings demonstrated that demographic and socio-economic factors, specifically age, income, living environment, leisure activities, and education level, significantly influence network formation. Importantly, age, environmental conditions, satisfaction with public transportation, and walking frequency were closely associated with the evolution of formal networks. These results highlight the importance of early community network assessments, which must consider distinct network traits to develop effective health promotion models. Utilizing SNA early in the assessment process can improve understanding of network dynamics and optimize the effectiveness of health interventions.

Machine Learning Model for Mild Cognitive Impairment Stage Based on Gait and MRI Images.

In patients with mild cognitive impairment (MCI), a lower level of cognitive function is associated with a higher likelihood of progression to dementia. In addition, gait disturbances and structural changes on brain MRI scans reflect cognitive levels. Therefore, we aimed to classify MCI based on cognitive level using gait parameters and brain MRI data. Eighty patients diagnosed with MCI from three dementia centres in Gangwon-do, Korea, were recruited for this study. We defined MCI as a Clinical Dementia Rating global score of ≥0.5, with a memory domain score of ≥0.5. Patients were classified as early-stage or late-stage MCI based on their mini-mental status examination (MMSE) z-scores. We trained a machine learning model using gait and MRI data parameters. The convolutional neural network (CNN) resulted in the best classifier performance in separating late-stage MCI from early-stage MCI; its performance was maximised when feature patterns that included multimodal features (GAIT + white matter dataset) were used. The single support time was the strongest predictor. Machine learning that incorporated gait and white matter parameters achieved the highest accuracy in distinguishing between late-stage MCI and early-stage MCI.

Hyperarousal-state of Insomnia Disorder in Wake-resting State Quantitative Electroencephalography.

Objective: : Insomnia is associated with elevated high-frequency electroencephalogram power in the waking state. Although affective symptoms (e.g., depression and anxiety) are commonly comorbid with insomnia, few reports distinguished objective sleep disturbance from affective symptoms. In this study, we investigated whether daytime electroencephalographic activity explains insomnia, even after controlling for the effects of affective symptoms. Methods: : A total of 107 participants were divided into the insomnia disorder (n = 58) and healthy control (n = 49) groups using the Mini-International Neuropsychiatric Interview and diagnostic criteria for insomnia disorder. The participants underwent daytime resting-state electroencephalography sessions (64 channels, eye-closed). Results: : The insomnia group showed higher levels of anxiety, depression, and insomnia than the healthy group, as well as increased beta [t(105) = -2.56, p = 0.012] and gamma [t(105) = -2.44, p = 0.016] spectra. Among all participants, insomnia symptoms positively correlated with the intensity of beta (r = 0.28, p ＜ 0.01) and gamma (r = 0.25, p ＜ 0.05) spectra. Through hierarchical multiple regression, the beta power showed the additional ability to predict insomnia symptoms beyond the effect of anxiety (ΔR2 = 0.041, p = 0.018). Conclusion: : Our results showed a significant relationship between beta electroencephalographic activity and insomnia symptoms, after adjusting for other clinical correlates, and serve as further evidence for the hyperarousal theory of insomnia. Moreover, resting-state quantitative electroencephalography may be a supplementary tool to assess insomnia.

Cross-cultural validation and measurement invariance of anxiety and depression symptoms: A study of the Brief Symptom Inventory (BSI) in 42 countries.

BACKGROUND: Depression and anxiety are among the most prevalent mental health issues experienced worldwide. However, whereas cross-cultural studies utilize psychometrically valid and reliable scales, fewer can meaningfully compare these conditions across different groups. To address this gap, the current study aimed to psychometrically assess the Brief Symptomatology Index (BSI) in 42 countries. METHODS: Using data from the International Sex Survey (N = 82,243; Mage = 32.39; SDage = 12.52; women: n = 46,874; 57 %), we examined the reliability of depression and anxiety symptom scores of the BSI-18, as well as evaluated evidence of construct, invariance, and criterion-related validity in predicting clinically relevant variables across countries, languages, genders, and sexual orientations. RESULTS: Results corroborated an invariant, two-factor structure across all groups tested, exhibiting excellent reliability estimates for both subscales. The 'caseness' criterion effectively discriminated among those at low and high risk of depression and anxiety, yielding differential effects on the clinical criteria examined. LIMITATIONS: The predictive validation was not made against a clinical diagnosis, and the full BSI-18 scale was not examined (excluding the somatization sub-dimension), limiting the validation scope of the BSI-18. Finally, the study was conducted online, mainly by advertisements through social media, ultimately skewing our sample towards women, younger, and highly educated populations. CONCLUSIONS: The results support that the BSI-12 is a valid and reliable assessment tool for assessing depression and anxiety symptoms across countries, languages, genders, and sexual orientations. Further, its caseness criterion can discriminate well between participants at high and low risk of depression and anxiety.

Cross-Cultural Adult ADHD Assessment in 42 Countries Using the Adult ADHD Self-Report Scale Screener.

OBJECTIVE: We analyzed adult ADHD symptoms in a cross-cultural context, including investigating the occurrence and potential correlates of adult ADHD and psychometric examination of the Adult ADHD Self-Report Scale (ASRS) Screener. METHOD: Our analysis is based on a large-scale research project involving 42 countries (International Sex Survey, N=72,627, 57% women, Mage=32.84; SDage=12.57). RESULTS: The ASRS Screener demonstrated good reliability and validity, along with partial invariance across different languages, countries, and genders. The occurrence of being at risk for adult ADHD was relatively high (21.4% for women, 18.1% for men). The highest scores were obtained in the US, Canada, and other English-speaking Western countries, with significantly lower scores among East Asian and non-English-speaking European countries. Moreover, ADHD symptom severity and occurrence were especially high among gender-diverse individuals. Significant associations between adult ADHD symptoms and age, mental and sexual health, and socioeconomic status were observed. CONCLUSIONS: Present results show significant cross-cultural variability in adult ADHD occurrence as well as highlight important factors related to adult ADHD. Moreover, the importance of further research on adult ADHD in previously understudied populations (non-Western countries) and minority groups (gender-diverse individuals) is stressed. Lastly, the present analysis is consistent with previous evidence showing low specificity of adult ADHD screening instruments and contributes to the current discussion on accurate adult ADHD screening and diagnosis.

Personalized virtual reality exposure for panic disorder and agoraphobia: A preliminary neurophysiological study.

BACKGROUND: Personalization is considered an important principle in virtual reality (VR) exposure therapy. We aimed to identify whether personalized VR exposure could provoke increased anxiety in patients with panic disorder and agoraphobia as it is considered the first step in successful treatment for anxiety. METHODS: We performed a double-arm, one-day preliminary study among 28 patients with panic disorder and agoraphobia. Three sessions of VR exposure, including a theater, train, and elevator scenario, were conducted in two groups. In the personalized group (n = 14), the brightness and crowd density were customized based on a pre-assessment. In the control group (n = 14), these conditions were fully randomized. Self-reported anxiety, heart rate, skin conductance, and electroencephalography were measured before, during, and after the VR sessions. RESULTS: In the later VR sessions, higher self-reported anxiety levels measured by the Visual Analogue Scale were observed in the personalized exposure group. Increased heart rates during and after the VR sessions were observed in the personalized group. The changes in skin conductance peaks were not significantly different between the groups, but the increase in skin conductance was associated with the participants' perception of presence. The electroencephalogram showed widespread increases in alpha waves in the frontal and temporal areas of the brain in the personalized group than in the control group. CONCLUSION: Personalized VR exposure elicits stronger anxiogenic effects in patients with panic disorder and agoraphobia as suggested by self-report and neurophysiological data. Personalization of VR exposure has the potential for effective behavioral therapy.

The association between adverse childhood experiences and self-harm among South Korean children and adolescents: a cross-sectional study.

PURPOSE: Adolescent self-harm is a public health problem. Research suggests a link between adverse childhood experiences (ACEs) and self-destructive behaviors. Few studies, however, have examined the effects of ACEs on self-harm among Asian adolescents. This study explored the association between lifetime ACEs and a history of self-harm among Korean children and adolescents in elementary, middle, and high schools. METHODS: A cross-sectional, retrospective medical record review was conducted on a dataset of a national psychiatrist advisory service for school counselors who participated in the Wee Doctor Service from January 1 to December 31, 2020. The data were analyzed using multiple logistic regression to predict self-harm. RESULTS: Student cases (n=171) were referred to psychiatrists by school counselors for remote consultation. Multiple logistic regression analyses revealed that the odds of self-harm were higher among high school students (adjusted odds ratio [aOR]=4.97; 95% confidence interval [CI]=1.94-12.76), those with two or more ACEs (aOR=3.27; 95% CI=1.43-7.47), and those with depression (aOR=3.06; 95% CI=1.32-7.10). CONCLUSION: The study's findings provide compelling evidence that exposure to ACEs can increase vulnerability to self-harm among Korean students. Students with a history of ACEs and depression, as well as high school students, require increased attention during counseling. School counselors can benefit from incorporating screening assessment tools that include questions related to ACEs and depression. Establishing a systematic referral system to connect students with experts can enhance the likelihood of identifying self-harm tendencies and offering the essential support to prevent self-harm.

Assessment of Equine Influenza Virus Status in the Republic of Korea from 2020 to 2022.

Equine influenza virus (EIV) causes acute respiratory disease in horses and belongs to the influenza A virus family Orthomyxoviridae, genus Orthomyxovirus. This virus may have severe financial implications for the horse industry owing to its highly contagious nature and rapid transmission. In the Republic of Korea, vaccination against EIV has been practiced with the active involvement of the Korea Racing Authority since 1974. In this study, we monitored the viral RNA for EIV using PCR, as well as the antibody levels against 'A/equine/South Africa/4/03 (H3N8, clade 1)', from 2020 to 2022. EIV was not detected using RT-PCR. The seropositivity rates detected using a hemagglutination inhibition assay were 90.3% in 2020, 96.7% in 2021, and 91.8% in 2022. The geometric mean of antibody titer (GMT) was 83.4 in 2020, 135.7 in 2021, and 95.6 in 2022. Yearlings and two-year-olds in training exhibited lower positive rates (59.1% in 2020, 38.9% in 2021, and 44.1% in 2022) than the average. These younger horses may require more attention for vaccination and vaccine responses against EIV. Continuous surveillance of EIV should be performed to monitor the prevalence and spread of this disease.

Psychometric properties of the Alcohol Use Disorders Identification Test (AUDIT) across cross-cultural subgroups, genders, and sexual orientations: Findings from the International Sex Survey (ISS).

INTRODUCTION: Despite being a widely used screening questionnaire, there is no consensus on the most appropriate measurement model for the Alcohol Use Disorders Identification Test (AUDIT). Furthermore, there have been limited studies on its measurement invariance across cross-cultural subgroups, genders, and sexual orientations. AIMS: The present study aimed to examine the fit of different measurement models for the AUDIT and its measurement invariance across a wide range of subgroups by country, language, gender, and sexual orientation. METHODS: Responses concerning past-year alcohol use from the participants of the cross-sectional International Sex Survey were considered (N = 62,943; Mage: 32.73; SD = 12.59). Confirmatory factor analysis, as well as measurement invariance tests were performed for 21 countries, 14 languages, three genders, and four sexual-orientation subgroups that met the minimum sample size requirement for inclusion in these analyses. RESULTS: A two-factor model with factors describing 'alcohol use' (items 1-3) and 'alcohol problems' (items 4-10) showed the best model fit across countries, languages, genders, and sexual orientations. For the former two, scalar and latent mean levels of invariance were reached considering different criteria. For gender and sexual orientation, a latent mean level of invariance was reached. CONCLUSIONS: In line with the two-factor model, the calculation of separate alcohol-use and alcohol-problem scores is recommended when using the AUDIT. The high levels of measurement invariance achieved for the AUDIT support its use in cross-cultural research, capable also of meaningful comparisons among genders and sexual orientations.

Social Stigma and Discrimination Toward People With Drug Addiction: A National Survey in Korea.

OBJECTIVE: This study aims to understand the attitudes, stigma, and discrimination of the general adult population toward drug addiction. METHODS: We conducted a cross-sectional nationwide survey with 1,020 Korean adults using an Internet web-based panel. Self-reported data were collected on demographics, experience with substance abuse, perceptions of narcotic analgesic use, beliefs about the legalization of cannabis use, coping with substance abuse and addiction, and perceptions of drug risks. All statistical analysis in this study utilized the IBM SPSS Statistics 26 program. RESULTS: In this study, 1.6% of the participants reported abuse of opioid analgesics, 88.0% reported negative perceptions of drug addiction, and 76.9% reported agreeing to unfair treatment of drug addicts. Logistic regression analysis found that perceived stigma was more prevalent among women (odd ratio [OR]=2.087, p<0.01), old adults (OR=1.939, p<0.01), those with no personal experience of opioid misuse (OR=8.172, p<0.05), and those who were non-smoking (OR=2.011, p<0.01). In addition, the discriminatory attitude was more prevalent among participants with higher income (OR=1.989, p<0.001) and those who are non-smoking (OR=1.608, p<0.05). CONCLUSION: This study provides information and guidelines for public intervention in drug addiction by identifying factors influencing social stigma and discriminatory behaviors toward drug addiction. The findings suggest that education on drug addiction prevention for the general adult population is necessary, and this education should include knowledge on coping with drug addiction and reducing stigma and discrimination toward drug addicts.

Relationship of Neural Correlates of Gait Characteristics and Cognitive Dysfunction in Patients with Mild Cognitive Impairment.

Background: Some patients with mild cognitive impairment (MCI) experience gait disturbances. However, there are few reports on the relationship between gait disturbance and cognitive function in patients with MCI. Therefore, we investigated the neural correlates of gait characteristics related to cognitive dysfunction. Methods: Eighty patients diagnosed with MCI from three dementia centers in Gangwon-do, Korea, were recruited for this study. We defined MCI as a Clinical Dementia Rating global score of 0.5 or higher, with a memory domain score of 0.5 or greater. The patients were classified as having either higher or lower MMSE and the groups were based on their Mini Mental Status Examination z-scores. Multiple logistic regression analysis was performed to examine the association between the gait characteristics and cognitive impairment. Analyses included variables such as age, sex, years of education, number of comorbidities, body mass index, and height. Results: Gait velocity, step count, step length, heel-to-heel base support, swing and stance phase duration, and support time were associated with cognitive function. A decrease in gray matter volume in the right pericalcarine area was associated with gait characteristics related to cognitive dysfunction. An increase in the curvature of gray matter in the right entorhinal, right lateral orbitofrontal, right cuneus, and right and left pars opercularis areas was also associated with gait characteristics related to cognitive dysfunction. Conclusion: Since gait impairment is an important factor in determining activities of daily living in patients with mild cognitive impairment, the evaluation of gait and cognitive functions in patients with mild cognitive impairment is important.

Dry-milled flour rice 'Seolgaeng' harbors a mutated fructose-6-phosphate 2-kinase/fructose-2,6-bisphosphatase2.

'Seolgaeng', an opaque-endosperm rice (Oryza sativa) mutant, is used to prepare high-quality dry-milled rice flour. The mutation causing its opaque-endosperm phenotype was unknown. Map-based cloning identified a missense mutation in the gene FRUCTOSE-6-PHOSPHATE 2-KINASE/FRUCTOSE-2,6-BISPHOSPHATASE 2 (OsF2KP2) in Seolgaeng. Transfer DNA insertion and clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated nuclease 9 (Cas9)-induced f2kp2 mutants exhibited opaque endosperm. Rice harbors another F2KP gene, OsF2KP1. CRISPR/Cas9-induced double mutants of OsF2KP1 and OsF2KP2 (f2kp-d) possessed more opaque endosperm compared to f2kp2 single mutants, whereas the endosperm of the f2kp1 single mutant was normal. Grain hardness and damaged starch content were significantly reduced in f2kp2 mutants compared to the wild type and f2kp1. Amylose content was lower than normal in f2kp2 mutants but not f2kp1. Grain hardness and amylose content were much lower in f2kp-d than in f2kp2. Starch polymerization analysis revealed altered amylopectin structure in f2kp2 and f2kp-d mutants. F2KP activity was lower in f2kp2 and much lower in the double mutants when compared to the wild types, but f2kp1 showed no significant difference. In coleoptiles, hypoxia induced OsF2KP2 expression but downregulated OsF2KP1. These results suggest that OsF2KP2 functions as the main F2KP isoform in endosperm experiencing hypoxia, but OsF2KP1 may partially compensate for the absence of OsF2KP2. We propose that F2KP has a crucial role in inorganic pyrophosphate-utilizing energy metabolism for starch biosynthesis in rice endosperm.