High-Performance Intrinsically Stretchable Polymer Solar Cell with Record Efficiency and Stretchability Enabled by Thymine-Functionalized Terpolymer.

Designing new polymer semiconductors for intrinsically stretchable polymer solar cells (IS-PSCs) with high power conversion efficiency (PCE) and durability is critical for wearable electronics applications. Nearly all high-performance PSCs are constructed using fully conjugated polymer donors (PD) and small-molecule acceptors (SMA). However, a successful molecular design of PDs for high-performance and mechanically durable IS-PSCs without sacrificing conjugation has not been realized. In this study, we design a novel thymine side chain terminated 6,7-difluoro-quinoxaline (Q-Thy) monomer and synthesize a series of fully conjugated PDs (PM7-Thy5, PM7-Thy10, PM7-Thy20) featuring Q-Thy. The Q-Thy units capable of inducing dimerizable hydrogen bonding enable strong intermolecular PD assembly and highly efficient and mechanically robust PSCs. The PM7-Thy10:SMA blend demonstrates a combination of high PCE (>17%) in rigid devices and excellent stretchability (crack-onset value >13.5%). More importantly, PM7-Thy10-based IS-PSCs show an unprecedented combination of PCE (13.7%) and ultrahigh mechanical durability (maintaining 80% of initial PCE after 43% strain), illustrating the promising potential for commercialization in wearable applications.

Needs Assessment for the Development of Training Curricula for Internal Medicine Residents.

BACKGROUND: Patient-centered outcomes can be achieved when common core and specialist competencies are achieved in a balanced manner. This study was conducted to assess the need to fill the gap between the defined competencies and learners' achievement, in order to improve the internal medicine (IM) training education curriculum for promoting patient-centered outcomes. METHODS: A cross-sectional online survey was conducted. The participants were 202 IM specialists who obtained board certification in 2020-2021. We developed a questionnaire to investigate the self-evaluation of common core competencies and achievement level of IM essential competencies. For analysis, frequency tests, paired t-test, Borich priority formula, and χ² were performed. RESULTS: In common core competencies, IM specialists recognized that their achievement levels in all competency categories were lower than their importance level (P < 0.001), and the highest educational demands were related to self-management. They assessed their five essential procedure skill levels as novice or advanced beginner status. The achievement level for the essential symptoms and signs that IM specialists should be able to manage was predominantly competent level. However, on average, 34.9% answered that they had never assessed during training for essential skills, and 29.7% answered the same for essential symptoms and signs. CONCLUSION: We identified the priorities of core competencies, the level of achievement in essential procedures and patient care with essential symptoms and signs for IM training, and the related educational methods and assessment status. This study is expected to be used as basic data for developing and revising IM training educational curriculum.

Facial Rejuvenation Using a Mixture of Calcium Hydroxylapatite Filler and Hyaluronic Acid Filler.

Calcium hydroxylapatite filler is a popular dermal filler, as it provides long-lasting results. However, it sometimes undergoes unexpected early volume loss, due to rapid gel absorption before neocollagenesis. To compensate for this phenomenon, hyaluronic acid filler was added to calcium hydroxylapatite filler for injection as a mixture. Twenty-five patients who scored 1 or 2 on the Merz 5-point scale for the nasolabial fold and jawline were injected with 3.0 mL of the mixture. The mixture was prepared with 1.0 mL of hyaluronic acid filler, 0.5 mL of lidocaine, and 1.5 mL of calcium hydroxylapatite filler. A visual analog scale (VAS) and the 5-point global satisfaction scale (GSS) were used for objective and subjective assessments. In a subset of patients, for histologic analysis, 0.1 mL of the mixture and 0.1 mL of only calcium hydroxylapatite filler were injected into the right and left postauricular areas, respectively. The histologic analysis was performed 6 months after implantation. The mean VAS and GSS scores for both sets of wrinkles were above "fair" at every follow-up, including at short-term and long-term periods. The skin biopsies from both postauricular areas from selected patients showed increased dermal collagen bundles without inflammation. The mixture of calcium hydroxylapatite filler and hyaluronic acid filler maintained constant volume with high satisfaction, as hyaluronic acid filler compensated for the unexpected early volume loss of calcium hydroxylapatite filler. This procedure can be applied safely, and it is also convenient, because no retouching procedure is needed.

Grouping schemes of welding fume exposure in shipyard welders.

Welding fume exposure can increase the risk of chronic obstructive pulmonary disease (COPD). The aim of this study was to evaluate the optimal grouping schemes of welding fume exposure in shipyard welders for future accurate examination of the association between welding fume exposure and COPD. Industrial hygiene records, including welding fume measurements between 2002 and 2009 were collected from a shipyard. A total of 2,360 personal welding fume measurements was compiled with a geometric mean of 1.66 mg/m3 and a geometric standard deviation of 4.02. Welding jobs were categorized into 8 groups. There were 9 working areas. To obtain the optimal grouping scheme, various grouping schemes were created using job, area, and job*area combination. To compare various grouping schemes, contrast and precision were calculated for each grouping scheme. For all measurement data, group mean ranking method created by ranking geometric means of the job*area combination into 3 groups (group mean ranking method) showed the best contrast and precision values among various grouping schemes, followed by grouping based on the job. For a subset of the data excluding job*area combinations with less than 10 measurements, grouping based on the job showed greater contrast than group mean ranking method, while for other subsets, including only repeated measurement data or further excluding job*area combinations with less than 10 measurements from the repeated measurement subset, group mean ranking method showed greater contrast than grouping based on the job. Our results showed that group mean ranking or grouping based on the job could be a candidate for the optimal grouping schemes in this shipyard. Our efforts for optimal grouping scheme may aid future cohort study to elucidate the association between welding fume exposure and COPD.

Changes of oxidative/antioxidative parameters and DNA damage in firefighters wearing personal protective equipment during treadmill walking training.

[Purpose] The purpose of this study was to investigate the influence of personal protective equipment on the oxidant/antioxidant parameters and DNA damage in firefighters during training and recovery. [Subjects and Methods] Twelve male nonsmoking volunteer firefighters (35.1 ± 7.2 years) underwent two maximal treadmill training (9 METs, 6 km/h), within 2 weeks, one in regular clothes and one in personal protective equipment weighing 22.1 kg. Blood samples were obtained before, right after, and 40 min after training. Plasma conjugated dienes, total radical trapping antioxidant potential, erythrocytes antioxidant enzymes activities, and leukocyte DNA damage were measured. [Results] Wearing personal protective equipment during treadmill walking training resulted in increases of plasma conjugated dienes, total radical trapping antioxidant potential, and leukocyte DNA resistance to oxidative stress, which were recovered after in 40 min of rest. Erythrocyte antioxidant enzymes activities remained unchanged during the training either with regular clothes or personal protective equipment. [Conclusion] These results suggest that wearing personal protective equipment during firefighting work could induce oxidative stress, which was enough to produce DNA damage in leukocytes.

Importance of remission and residual somatic symptoms in health-related quality of life among outpatients with major depressive disorder: a cross-sectional study.

BACKGROUND: Major depressive disorder (MDD) is strongly associated with an impaired quality of life (QoL), which is itself affected by various factors. Symptom-oriented ratings poorly reflect the impact of disease on the QoL and level of functioning of the mental health of subjects. The purpose of this study was to assess health-related QoL (HRQoL) using preference-based measures in outpatients with MDD with regard to their remission achievement and clinical factors affecting the HRQoL. METHODS: This was a cross-sectional observational study. We recruited 811 patients with MDD from 14 psychiatric outpatient clinics in Korea. They were divided into three groups as follows: a new visit group (n = 287), a remitted group (n = 235), and a non-remitted group (n = 289). The 17-item Hamilton Depression Rating Scale was used to assign patients to the remitted or non-remitted group. The general HRQoL was assessed with the EuroQol 5D (EQ-5D), using both the EQ-5D index score and the EuroQol Visual Analog Scale (EQ-VAS). The disease-specific HRQoL was assessed with the Quality of Life Enjoyment and Satisfaction Questionnaire Short Form (Q-LES-Q-SF). RESULTS: The non-remitted group showed a significant impairment of HRQoL in view of the subscales of EQ-5D index scores, EQ-VAS, and Q-LES-Q-SF. The EQ-5D index score in the remitted group was 0.77 ± 0.10, while it was 0.57 ± 0.23 in the non-remitted group and 0.58 ± 0.24 in the new visit group (p < 0.0001). The EQ-VAS scores for the remitted and non-remitted groups were 72.5 ± 16.6 and 50.9 ± 20.3, respectively (p < 0.0001). Likewise, patients with remission had the Q-LES-Q-SF total score of 46.5 ± 8.8, whereas those with non-remission reported 36.7 ± 7.7 (p < 0.0001). The symptom severity measured by the Depression and Somatic Symptoms Scale was significantly correlated with the HRQoL. Furthermore, patients with severe somatic symptoms showed a significantly lower EQ-5D index score (0.54 ± 0.24) than those with mild/moderate somatic symptoms (0.75 ± 0.12; p = 0.002). CONCLUSION: Non-remitted MDD patients, especially those with more severe somatic symptoms, show a distinct impairment of HRQoL and more clinical symptoms, suggesting the importance of achieving remission in the treatment of MDD.

Development of the Korean construction job exposure matrix (KoConJEM) based on experts' judgment using the 60 consolidated occupations for construction workers.

BACKGROUND: This study was conducted as an effort to develop a Korean construction job exposure matrix (KoConJEM) based on 60 occupations recently consolidated by the construction workers mutual aid association for use by the construction industry. METHODS: The probability, intensity, and prevalence of exposure to 26 hazardous agents for 60 consolidated occupations were evaluated as binary (Yes/No) or four categories (1 to 4) by 30 industrial hygiene experts. The score for risk was calculated by multiplying the exposure intensity by the prevalence of exposure. Fleiss' kappa for each hazardous agent and occupation was used to determine agreement among the 30 experts. The JEM was expressed on a heatmap and a web-based dashboard to facilitate comparison of factors affecting exposure according to each occupation and hazardous agent. RESULTS: Awkward posture, heat/cold, heavy lifting, and noise were hazardous agents regarded as exposure is probable by at least one or more experts in all occupations, while exposure to asphalt fumes was considered hazardous in the smallest number of occupations (n = 5). Based on the degree of agreement among experts, more than half of the harmful factors and most occupations showed fair to good results. The highest risk value was 16 for awkward posture for most occupations other than safety officer. CONCLUSIONS: The KoConJEM provides information on the probability, intensity, and prevalence of exposure to harmful factors, including most occupations employing construction workers; therefore, it may be useful in the conduct of epidemiological studies on assessment of health risk for construction workers.

Study of mechanical degradation of freestanding ALD Al2O3 by a hygrothermal environment and a facile protective method for environmentally stable Al2O3: toward highly reliable wearable OLEDs.

Al2O3 deposited via atomic layer deposition (ALD) has been used as an insulating and barrier film for thin-film transistors, organic electronics, and microelectromechanical systems. However, ALD Al2O3 films are easily degraded by hydrolysis under harsh hygrothermal conditions, owing to their poor environmental stability. In this study, the mechanical properties and water-vapor transmission rate (WVTR) of environmentally degraded Al2O3 films were investigated by varying the temperature and relative humidity (RH). The hygrothermal environment led to surface and pinhole-concentrated degradation based on aluminum hydroxide, which caused an increased WVTR and reduced elongation of the films in harsher environments. In particular, the elongation of the degraded Al2O3 films was reduced to 0.3%, which is one-third of that of as-deposited Al2O3, and their WVTR increased on the order of 10-1 g m-2 day-1, which is more than 1000 times that of as-deposited Al2O3. Therefore, we introduced a functional silane-based inorganic-organic hybrid layer (silamer) onto the Al2O3 films to improve their environmental stability. The silamer helped preserve the characteristics of Al2O3 films by forming a strong and continuous aluminate phase of Al-O-Si at their interface in hygrothermal environments. Furthermore, the silamer-capped Al2O3 was shown to be an environmentally stable encapsulation for application in wearable organic devices.

Safety and Effectiveness of Empagliflozin in Korean Patients with Type 2 Diabetes Mellitus: Results from a Nationwide Post-Marketing Surveillance.

BACKGROUND: To evaluate the safety and effectiveness of empagliflozin in routine clinical settings, we collected and assessed the clinical profiles of Korean patients with type 2 diabetes mellitus. METHODS: This was a post-marketing surveillance study of empagliflozin 10 and 25 mg. Information on adverse events and adverse drug reactions (ADRs) was collected as safety data sets. Available effectiveness outcomes, including glycosylated hemoglobin (HbA1c) level, fasting plasma glucose, body weight, and blood pressure, were assessed. RESULTS: The incidence rate of ADRs was 5.14% in the safety dataset (n=3,231). Pollakiuria, pruritis genital, and weight loss were the most common ADRs. ADRs of special interest accounted for only 1.18%, and there were no serious events that led to mortality or hospitalization. In the effectiveness data set (n=2,567), empagliflozin significantly reduced the mean HbA1c level and body weight during the study period by -0.68%±1.39% and -1.91±3.37 kg (both P<0.0001), respectively. In addition, shorter disease duration, absence of dyslipidemia, and higher baseline HbA1c levels were identified as the clinical features characteristic of a "responder" to empagliflozin therapy. CONCLUSION: Empagliflozin is a safe and potent glucose-lowering drug in routine use among Korean patients with type 2 diabetes mellitus. It is expected to have better glycemic efficacy in Korean patients with poorly controlled type 2 diabetes mellitus.

Efficient Imidazolium-Biomolecule Interaction-Assisted Amplified Quenching for Ultrasensitive Detection of Heparin.

Detection of heparin (HP) under physiological conditions is difficult due to the presence of biological obstructions including proteins and lipids. Thus, it is highly challenging to selectively detect HP and to increase its sensitivity in complex systems. Here, we report the detection of HP at nanomolar levels via efficient imidazolium-HP interaction-assisted fluorescence quenching amplification. The self-assembled pyrenyl aggregates are devised as a conduit for efficient exciton transport, which induces amplified fluorescence quenching for HP detection. This amplified quenching is enhanced by introducing an imidazolium receptor designed to have a high affinity to HP via electrostatic and/or additional interactions with C2 protons, resulting in a very high Stern-Volmer quenching constant of approximately 1.17×108  M-1 .

Polymer Acceptors with Flexible Spacers Afford Efficient and Mechanically Robust All-Polymer Solar Cells.

High efficiency and mechanical robustness are both crucial for the practical applications of all-polymer solar cells (all-PSCs) in stretchable and wearable electronics. In this regard, a series of new polymer acceptors (PA s) is reported by incorporating a flexible conjugation-break spacer (FCBS) to achieve highly efficient and mechanically robust all-PSCs. Incorporation of FCBS affords the effective modulation of the crystallinity and pre-aggregation of the PA s, and achieves the optimal blend morphology with polymer donor (PD ), increasing both the photovoltaic and mechanical properties of all-PSCs. In particular, an all-PSC based on PYTS-0.3 PA incorporated with 30% FCBS and PBDB-T PD demonstrates a high power conversion efficiency (PCE) of 14.68% and excellent mechanical stretchability with a crack onset strain (COS) of 21.64% and toughness of 3.86 MJ m-3 , which is significantly superior to those of devices with the PA without the FCBS (PYTS-0.0, PCE = 13.01%, and toughness = 2.70 MJ m-3 ). To date, this COS is the highest value reported for PSCs with PCEs of over 8% without any insulating additives. These results reveal that the introduction of FCBS into the conjugated backbone is a highly feasible strategy to simultaneously improve the PCE and stretchability of PSCs.

Intrinsically Stretchable, Highly Efficient Organic Solar Cells Enabled by Polymer Donors Featuring Hydrogen-Bonding Spacers.

Intrinsically stretchable organic solar cells (IS-OSCs), consisting of all stretchable layers, are attracting significant attention as a future power source for wearable electronics. However, most of the efficient active layers for OSCs are mechanically brittle due to their rigid molecular structures designed for high electrical and optical properties. Here, a series of new polymer donors (PD s, PhAmX) featuring phenyl amide (N1 ,N3 -bis((5-bromothiophen-2-yl)methyl)isophthalamide, PhAm)-based flexible spacer (FS) inducing hydrogen-bonding (H-bonding) interactions is developed. These PD s enable IS-OSCs with a high power conversion efficiency (PCE) of 12.73% and excellent stretchability (PCE retention of >80% of the initial value at 32% strain), representing the best performances among the reported IS-OSCs to date. The incorporation of PhAm-based FS enhances the molecular ordering of PD s as well as their interactions with a Y7 acceptor, enhancing the mechanical stretchability and electrical properties simultaneously. It is also found that in rigid OSCs, the PhAm5:Y7 blend achieves a much higher PCE of 17.5% compared to that of the reference PM6:Y7 blend. The impact of the PhAm-FS linker on the mechanical and photovoltaic properties of OSCs is thoroughly investigated.

Recurrent pancreatitis in the setting of gallbladder agenesis, ansa pancreatica, Santorinicoele and eventual intraductal papillary mucinous neoplasia (IPMN).

Gallbladder agenesis is a rare condition. Patients with gallbladder agenesis can present with biliary type symptoms and rarely pancreatitis. We present the case of a 35-year-old gentleman who was admitted and treated for recurrent pancreatitis on a background of gallbladder agenesis, ansa pancreatica and Santorinicoele. He has had several admissions with pancreatitis and has had multiple imaging modalities during these admissions which we delineate. We discuss this rare anatomical variant and describe the course and management of his illness leading up to his eventual diagnosis of intraductal papillary neoplasia (IPMN).

Identification of an ISR-related metabolite produced by Pseudomonas chlororaphis O6 against the wildfire pathogen pseudomonas syringae pv.tabaci in tobacco.

Pseudomonas chlororaphis O6 exhibits induced systemic resistance (ISR) against P. syringae pv. tabaci in tobacco. To identify one of the ISR metabolites, O6 cultures were extracted with organic solvents, and the organic extracts were subjected to column chromatography followed by spectroscopy analyses. The ISR bioassay-guided fractionation was carried out for isolation of the metabolite. Highresolution mass spectrometric analysis of the metabolite found C(9)H(9)O(3)N with an exact mass of 179.0582. LC/MS analysis in positive mode showed an (M+H)(+) peak at m/zeta 180. Nuclear magnetic resonance ((1)H, (13)C) analyses identified all protons and carbons of the metabolite. Based on the spectroscopy data, the metabolite was identified 4-(aminocarbonyl) phenylacetate (4-ACPA). 4-ACPA applied at 68.0 mM exhibited ISR activity at a level similar 1.0 mM salicylic acid. This is the first report to identify an ISR metabolite produced by P. chlororaphis O6 against the wildfire pathogen P. syringae pv. tabaci in tobacco.

Electrostatic and hydrophobic interactions of lipid-associated α-synuclein: The role of a water-limited interfaces in amyloid fibrillation.

Human α­synuclein (αSyn) is an intrinsically disordered protein (IDP) whose biological and pathological functions in brain neuronal cells have not yet been fully elucidated. αSyn intrinsically participates in aiding neurotransmitter trafficking through αSyn the association with lipid membranes. However, lipid-associated states of αSyn also induce amyloid self-assembly that is linked to the pathogenesis of various synucleinopathies. These contradicting actions arise from the limited water content near lipid-water interfaces that controls αSyn electrostatic and hydrophobic interactions. Thus, understanding the molecular interactions between αSyn and lipid membranes in the presence of water molecules is critical in elucidating the pivotal role of lipid-associated αSyn in amyloid self-assembly. In this review, we describe how the membrane interface controls electrostatic and hydrophobic interactions of lipid-associated αSyn. Moreover, membrane amyloid self-assembly of αSyn will be further discussed with regards to the structural dynamics of lipid-associated αSyn and water molecules near the interface.

Effects of Uric Acid on the Alterations of White Matter Connectivity in Patients with Major Depression.

OBJECTIVE: Uric acid is a non-enzymatic antioxidant associated with depression. Despite its known protective role in other brain disorders, little is known about its influence on the structural characteristics of brains of patients with major depressive disorder (MDD). This study explored the association between uric acid and characteristics of white matter (WM) in patients with MDD. METHODS: A total of 32 patients with MDD and 23 healthy controls (HCs) were examined. All participants were scored based on the Beck Depression Inventory and Beck Anxiety Inventory at baseline. All patients were also rated with the Hamilton Depression Rating Scale. We collected blood samples from all participants immediately after their enrollment and before the initiation of antidepressants in case of patients. Tract-based spatial statistics were used for all imaging analyses. RESULTS: Lower fractional anisotropy (FA) and higher radial diffusivity (RD) values were found in the MDD group than in the HC group. Voxelwise correlation analysis revealed that the serum uric acid levels positively correlated with the FA and negatively with the RD in WM regions that previously showed significant group differences in the MDD group. The correlated areas were located in the left anterior corona radiata, left frontal lobe WM, and left anterior cingulate cortex WM. CONCLUSION: The present study suggests a significant association between altered WM connectivity and serum uric acid levels in patients with MDD, possibly through demyelination.

Genome-scale analysis of resveratrol-induced gene expression profile in human ovarian cancer cells using a cDNA microarray.

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural compound found in large quantities, most notably in grapes and red wine, which has been shown to have anti-inflammatory, chemopreventive and anti-angiogenic effects. We examined whether resveratrol has any effect on growth and gene expression in the human ovarian cancer PA-1 cells. We show that resveratrol inhibits cell growth and induces apoptosis in PA-1 human ovarian cancer cells. We also investigated the effect of resveratrol on changes of global gene expression during resveratrol-induced growth inhibition and apoptosis in PA-1 cells using a human cDNA microarray with 7,448 sequence-verified clones. Out of the 7,448 genes screened, 118 genes were founded to be affected in their expression levels by more than 2-fold after 24-h treatment with 50 micro M resveratrol. Resveratrol treatment of PA-1 cells at the final concentration of 50 micro M for 6, 12, 24 and 48 h and gene expression patterns were analyzed by microarray. Clustering of the genes modulated more than 2-fold at three of the above times points divided the genes into 2 groups. Within these groups, there were specific subgroups of genes whose expressions were substantially changed at the specified time points. One of the most highly up-regulated genes found in this study was NAD(P)H quinone oxidoreductase 1(NQO-1), which has recently been shown to be involved in p53 regulation. Although the precise roles of genes whose expression levels were found to fluctuate after resveratrol treatment remain to be elucidated, we hope that the new view of gene expression in human ovarian cancer cells following resveratrol exposure, as offered by this study, provides clues for the mechanism of resveratrol action.

A case of complicated silicosis with a complex clinical course in a glass manufacturing worker.

We reported a case of complicated silicosis that occurred in a glass manufacturing plant worker who had presumably been exposed to low-concentration free silica for almost 20 years. To the best of our knowledge this report is the first in the Republic of Korea. The physician's first impression was cancer since the enlargement of neck and supraclavicuar lymph nodes had clearly progressed and metastasis was suspected in ultrasonography. However, it turned out to be reactive hyperplasia and anthracosis. Although lung cancer was suspected and tests were performed in 2 hospitals due to repetitive cough and dyspnea, along with weight loss of approximately 10% over the course of 7 months, the patient was eventually diagnosed with complicated silicosis and pneumothorax occurred after 1 year. Herein, we report this case with a literature review.

Localized abnormalities in the cingulum bundle in patients with schizophrenia: a Diffusion Tensor tractography study.

The cingulum bundle (CB) connects gray matter structures of the limbic system and as such has been implicated in the etiology of schizophrenia. There is growing evidence to suggest that the CB is actually comprised of a conglomeration of discrete sub-connections. The present study aimed to use Diffusion Tensor tractography to subdivide the CB into its constituent sub-connections, and to investigate the structural integrity of these sub-connections in patients with schizophrenia and matched healthy controls. Diffusion Tensor Imaging scans were acquired from 24 patients diagnosed with chronic schizophrenia and 26 matched healthy controls. Deterministic tractography was used in conjunction with FreeSurfer-based regions-of-interest to subdivide the CB into 5 sub-connections (I1 to I5). The patients with schizophrenia exhibited subnormal levels of FA in two cingulum sub-connections, specifically the fibers connecting the rostral and caudal anterior cingulate gyrus (I1) and the fibers connecting the isthmus of the cingulate with the parahippocampal cortex (I4). Furthermore, while FA in the I1 sub-connection was correlated with the severity of patients' positive symptoms (specifically hallucinations and delusions), FA in the I4 sub-connection was correlated with the severity of patients' negative symptoms (specifically affective flattening and anhedonia/asociality). These results support the notion that the CB is a conglomeration of structurally interconnected yet functionally distinct sub-connections, of which only a subset are abnormal in patients with schizophrenia. Furthermore, while acknowledging the fact that the present study only investigated the CB, these results suggest that the positive and negative symptoms of schizophrenia may have distinct neurobiological underpinnings.

Integrated analysis of diverse transcriptomic data from Arabidopsis reveals genetic markers that reliably and reproducibly respond to ionizing radiation.

Studies focused on the responses of plants to ionizing radiation are becoming more important due to the increased need for radiation-induced mutations, post-harvest or phytosanitary irradiation treatment of plants, and environmental monitoring of radioactive sites. To elucidate the influence of ionizing radiation on genome-wide transcription in plants, we performed integrated analysis of diverse transcriptomic data from different Arabidopsis samples and at various time points after γ irradiation or H2O2 treatment. The expression levels of most of the differentially expressed genes (DEGs) that were induced or repressed after γ irradiation returned to baseline levels of transcription within 12h, while some of these genes showed prolonged transcriptional changes. Expression of the DEGs did not correlate with genomic DNA methylation; however, there were substantial differences in DEG levels between the wild type and the cmt3-11 mutant, which has a defect in non-CG DNA methylation. Moreover, the proportion of the DEGs in common between 2 independent experiments using different batches of samples was only 12-18%. These results suggest that there is a diversity or randomness in radiation-induced physiological or phenotypic alterations. However, the results also indicated that 47 DEGs maintained a transcriptional change until 48h, and 7 of them, until 16d. Forty-five additional DEGs were found to be sustainably induced or repressed until 24h after γ irradiation regardless of sample-to-sample variation or genotype, and 4 or 2 of them, until 5d or 16d, respectively. Therefore, we suggest that the 4 γ-ray-responsive genes that showed sustainable transcriptional changes until day 5 would be reliable and reproducible genetic markers when evaluating the responsiveness of plants to γ-rays.