Association of adolescent postural tachycardia syndrome classifications with anxiety: a cross sectional study.

BACKGROUND: Postural tachycardia syndrome (POTS), a subset of orthostatic dysregulation, has been reported to be associated with anxiety. POTS can be classified into two forms based on the degree of tachycardia during orthostasis. Reportedly, POTS with decreased orthostatic heart rate increase is associated with suppressed cardiac parasympathetic activity and increased sympathetic activity in the supine position. In this study, the relationship between the two types of POTS and anxiety was evaluated in terms of autonomic function. METHODS: Fifty-two patients (23 male, age 10-15 years) who were diagnosed with POTS at the Department of Pediatrics, Osaka Medical and Pharmaceutical University from 2019 to 2021, completed a standing test and were accordingly classified into a Su group, with tachycardia from the supine position and a low heart rate increase on standing, a SI group, with a high heart rate increase during standing. They then completed the State-Trait Anxiety Scale for Children (STAIC) questionnaire. Autonomic function was assessed by frequency analysis (MemCalc method) based on heart rate, blood pressure changes, heart rate and blood pressure variability during the orthostatic test. RESULTS: Patients in the Su group had higher trait anxiety and state anxiety, lower cardiac parasympathetic activity (RR-HF) in the supine position, and greater variability in cardiac parasympathetic activity during orthostasis than were found for patients in the SI group. The Su group had a greater decrease in cardiac index on standing than that of the SI group. CONCLUSIONS: The Su group results may be partly attributed to chronically low venous return. We also found that patients in the Su group had low parasympathetic activity in the supine position, which may interact with the anxiety-prone characteristics of these patients. Therefore, it seems necessary to consider both physical and psychosomatic treatment approaches for patients with POTS.

Early detection of thermoacoustic instability in a staged single-sector combustor for aircraft engines using symbolic dynamics-based approach.

We experimentally conduct an early detection of thermoacoustic instability in a staged single-sector combustor using a novel methodology that combines symbolic dynamics and machine learning. We propose two invariants in this study: the determinisms of the joint symbolic recurrence plots DJ and the ordinal transition pattern-based recurrence plots DT. These invariants enable us to capture the phase synchronization between acoustic pressure and heat release rate fluctuations associated with a precursor of thermoacoustic instability. The latent space consisting of DJ and DT, which is obtained by a support vector machine in combination with the k-means clustering method, can appropriately determine a transitional regime between stable combustion and thermoacoustic instability.

Impacts of long-term coronavirus disease 2019 school closures on Japanese school children.

BACKGROUND: This study investigated the impact of coronavirus disease 2019 pandemic school closures on the mental health of school students with chronic diseases. METHODS: Questionnaires were distributed to students from 4th-9th grade diagnosed with chronic diseases at Osaka Medical College Hospital and their parents or caregivers. Questionnaires from 286 families were returned by mail after the schools reopened. The students were divided into the "psychosomatic disorder" group (group P, n = 42), the "developmental disorder" group (group D, n = 89), and the "other disease" group (group O, n = 155). Using students' self-reports on the Questionnaire for Triage and Assessment with 30 items, we assessed the proportion of students with a high risk of psychosomatic disorder in three groups. We investigated how the students requiring the support of somatic symptom (SS) felt about school during school closure. Further, using parents' and caregivers' answers, SS scores were calculated before and during school closure and after school reopening. RESULTS: The proportion of students with a high risk of developing psychosomatic disorder increased in all groups. For the students in Group P, the response "I did not want to think about school" indicated an increase in SS scores, and for the students in Group O, "I wanted to get back to school soon" indicated a decrease. Furthermore, especially in Group P students, SS scores decreased transiently during school closure and increased after school reopening. CONCLUSIONS: The impact of school closure on mental health differed depending on students' diagnoses and feelings about school during school closures.

Early intervention for psychosomatic symptoms of adolescents in school checkup.

BACKGROUND: The purpose of this study was to evaluate the efficacy of early medical intervention for psychosocial problems detected in adolescents in a school health checkup, with the broader goal of prevention of these problems in adolescents. METHODS: The Questionnaire for Triage and Assessment with 30 items score and scores for five subscales (physical symptoms, depression symptoms, anxiety symptoms, self-efficacy, and family function), and an investigation of lifestyle were determined in a school health checkup for 5th grade elementary to 3rd grade junior high school students. Forty-three children were found to be at high risk for psychosomatic disorder, of whom 18 then received a medical intervention (early intervention group) and 25 did not (non-intervention group). Fifty-seven children (outpatient group) treated for psychosomatic disorder for ≤3 months were also included in the study. The Questionnaire for Triage and Assessment with 30 items (QTA30) was completed by all participants every 3 months for 1 year and scores were compared among the groups. RESULTS: In the early intervention group, total Questionnaire for Triage and Assessment with 30 items scores; physical, depression, and anxiety symptoms; and unstable relationships with friends and teachers at school all significantly improved after 1 year compared to the first survey. None of these items improved in the non-intervention group, while the outpatient group had gradual improvement in all scores. Family function scores in the early intervention group improved over time, whereas those in the non-intervention group worsened. CONCLUSIONS: Early detection of children at high risk for psychosomatic disorder at a school health checkup and early medical intervention were useful for prevention of psychosomatic disorder in adolescents.

Late bedtime reflects QTA30 anxiety symptoms in adolescents in a school checkup.

BACKGROUND: In adolescence, physical symptoms may develop due to psychosocial problems but such problems are not fully evaluated in school medical checkups. The aim of this study was to compare lifestyle factors with psychosomatic symptoms in adolescents using the subscales of the Questionnaire for Triage and Assessment with 30 items (QTA30) in school health checkups. METHODS: The QTA30 was used in checkups for 3,414 students from the fifth grade of primary school to the third grade of junior high school in south Wakayama prefecture. The QTA is a self-completed questionnaire with five subscales of physical symptoms, depression symptoms, self-efficacy, anxiety symptoms, and family function. Each subscale is divided into three groups of clinical, borderline, and healthy, based on the subscale score. Subscale scores were compared with lifestyle items of gender, grade, habits, life events, and school attendance. RESULTS: The clinical rate for all subscales was significantly higher for a higher grade (P < 0.001). Anxiety symptoms were correlated with physical symptoms (r = 0.560). Anxiety and physical symptoms were significantly higher for students who went to bed at a later time with no absences in the last month and who had problems with friends and teachers (both P < 0.001). Family function correlated with self-efficacy (r = 0.418) but not with other subscales. Study time was most related to self-efficacy (P < 0.001). CONCLUSIONS: The QTA30 subscale scores facilitated detection of psychosomatic stress and latent risks of psychosomatic disease at an early stage. Thus, the use of the QTA30 in a school medical checkup may permit early intervention for psychosomatic stress in adolescents.

A Long-term Survival Case of Pulmonary Tumor Thrombotic Microangiopathy due to Gastric Cancer Confirmed by the Early Diagnosis based on a Transbronchial Lung Biopsy.

Pulmonary tumor thrombotic microangiopathy (PTTM) is an acute, progressive, and fatal disease. PTTM manifests as subacute respiratory failure with pulmonary hypertension, progressive right-sided heart failure, and sudden death. An antemortem diagnosis of PTTM is very difficult to obtain, and many patients die within several weeks. We herein report a case of PTTM diagnosed based on a transbronchial lung biopsy. In this case, we finally diagnosed PTTM due to gastric cancer because of its histological identity. The patient was administered chemotherapy, including angiogenesis inhibitors, against gastric cancer at an early age and survived for a long time.

Utility of the QTA30 in a school medical checkup for adolescent students.

BACKGROUND: In adolescence, physical symptoms may develop due to psychosocial problems, but such problems are not fully evaluated in school medical checkups. The aim of the study was to compare the characteristics of students with high and low scores on the Questionnaire for Triage and Assessment with 30 items (QTA30) in a school health checkup. METHODS: The QTA30 (a self-completed questionnaire) was used in checkups for 3,414 students from the 5th grade of primary schools to the 3rd grade of junior high schools in south Wakayama Prefecture. The students were divided into groups with high (QTA30 ≥ 37) and low (QTA30 < 37) risk for psychosomatic disorder. Eleven items, including gender, grade, lifestyle habits, and life events, were compared between these groups, and in subgroups with and without recent absence from school. RESULTS: The QTA30 response rate was 87.9%. The high-risk group had significantly more 3rd grade students (P< 0.001), females (P< 0.001), problems with teachers or friends (P< 0.001), and experience of bullying (P< 0.001), in addition to game playing for ≥2 h (P< 0.001), late bedtime (P< 0.001), and many absences (P< 0.001). Students in the high-risk group with no absences for 1 month regardless of age still had a late bedtime and problems with friends, and 76.4% of the high-risk students had not visited a medical institution. CONCLUSIONS: Use of the QTA30 facilitated detection of psychosomatic stress in school medical checkups, with latent risks of truancy detectable at an early phase. The QTA30 may thus be useful in early intervention for psychosomatic stress of adolescents.

Dynamic behavior of combustion instability in a cylindrical combustor with an off-center installed coaxial injector.

We have intensively studied the dynamic behavior of combustion instability in a cylindrical combustor with an off-center installed coaxial injector. The most interesting discovery in this study is the appearance of a deterministic chaos in a transition from a dynamically stable state to well-developed high-frequency thermoacoustic combustion oscillations with increasing the volume flow rate of nitrogen with which oxygen is diluted. The presence of deterministic chaos is reasonably identified by considering an extended version of the Sugihara-May algorithm [G. Sugihara and R. May, Nature 344, 734 (1990)] as a local predictor and the multiscale complexity-entropy causality plane based on statistical complexity.

Design and on-orbit operation of the Soft X-ray Spectrometer ADR on the Hitomi Observatory.

The Soft X-ray Spectrometer (SXS) instrument that flew on the Astro-H observatory was designed to perform imaging and spectroscopy of x-rays in the energy range of 0.2 to 13 keV with a resolution requirement of 7 eV or better. This was accomplished using a 6x6 array of x-ray microcalorimeters cooled to an operating temperature of 50 mK by an adiabatic demagnetization refrigerator (ADR). The ADR consisted of three stages in order to operate using either a 1.2 K superfluid helium bath or a 4.5 K Joule-Thomson (JT) cryocooler as its heat sink. The design was based on the following operating strategy. After launch, while liquid helium was present (cryogen mode), two of the ADR's stages would be used to single-shot cool the detectors, using the helium as a heat sink. When the helium was eventually depleted (cryogen-free mode), all three ADR stages would be used to continuously cool the helium tank to about 1.5 K, and to single-shot cool the detectors (to 50 mK), using the JT cryocooler as a heat sink. The Astro-H observatory, renamed Hitomi after its successful launch in February 2016, carried approximately 36 liters of helium into orbit. Based on measurements during ground testing, the average heat load on the helium was projected to be 0.66 mW, giving a lifetime of more than 4 years. On day 5, the helium had cooled to <1.4 K and ADR operation began, successfully cooling the detector array to 50 mK. The ADR's hold time steadily increased to 48 hours as the helium cooled to a temperature of 1.12 K. As the commissioning phase progressed, the ADR was recycled (requiring approximately 45 minutes) periodically, either in preparation for science observations or whenever the 50 mK stage approached the end of its hold time. In total, 18 cycles were completed by the time an attitude control anomaly led to an unrecoverable failure of the satellite on day 38. This paper presents the design, operation and on-orbit performance of the ADR in cryogen mode as the foreshortened mission did not provide an opportunity to test cryogen-free mode.

Autonomic nervous system function in adolescent migraineurs.

BACKGROUND: Migraine is a common and disabling neurological disorder. Studies on the relationship between migraine and the autonomic nervous system (ANS) have been inconclusive. Moreover, pediatric studies are extremely limited. Therefore, the present study investigated interictal ANS function in adolescent migraineurs. METHODS: We studied 21 patients with migraine and 26 healthy controls. Beat-to-beat blood pressure (BP) and heart rate (HR) were non-invasively and continuously measured in the supine and standing positions. ANS function was evaluated on power spectral analysis of HR variability and diastolic BP (DBP) variability. RESULTS: Heart rate and systolic BP were not different between the two groups in either the supine or standing position. DBP did not differ between groups in the standing position, but was significantly higher in migraineurs in the supine position. The vasoconstrictor index was significantly higher in migraineurs. High-frequency (HF) RR interval variability (RR-HF) and the ratio of the low-frequency (LF) to HF component of RR interval variability (RR-LF/HF) were not different between the two groups in both positions. The LF component of DBP variability (DBP-LF) in the supine position was significantly lower in migraineurs, while DBP-LF during standing in migraineurs was significantly higher than in controls. CONCLUSION: Migraineurs have significantly lower sympathetic vasomotor activity in the supine position, while sympathetic vasomotor activity was hyperresponsive during standing.

[A Case of Acute Respiratory Distress Syndrome (ARDS) Accompanied with Influenza (H1N1) 2009 Successfully Treated with Polymyxin B-immobilized Fiber Column-direct Hemoperfusion (PMX-DHP)].

A 51-year-old man was admitted to our hospital because of fever and diarrhea. Chest X-ray revealed consolidation in the left lower lung field. Ceftriaxone and minocycline were given empirically, under the suspicion of bacterial or atypical pneumonia. In spite of treatment with antibiotics, the disease rapidly progressed to systemic inflammatory response syndrome. The diagnosis of acute respiratory distress syndrome (ARDS) accompanied with influenza (H1N1) 2009 was made because of positive findings of real-time polymerase chain reaction. While multidisciplinary treatment was performed, his condition was further deteriorated suggesting the excessive pro-inflammatory mediators. To remove them, we conducted polymyxin-B immobilized column-direct hemoperfusion (PMX-DHP), and his general condition recovered successfully. PMX-DHP may be a useful treatment choice for ARDS accompanied with influenza.

Noninvasive analysis of metabolic changes following nutrient input into diverse fish species, as investigated by metabolic and microbial profiling approaches.

An NMR-based metabolomic approach in aquatic ecosystems is valuable for studying the environmental effects of pharmaceuticals and other chemicals on fish. This technique has also contributed to new information in numerous research areas, such as basic physiology and development, disease, and water pollution. We evaluated the microbial diversity in various fish species collected from Japan's coastal waters using next-generation sequencing, followed by evaluation of the effects of feed type on co-metabolic modulations in fish-microbial symbiotic ecosystems in laboratory-scale experiments. Intestinal bacteria of fish in their natural environment were characterized (using 16S rRNA genes) for trophic level using pyrosequencing and noninvasive sampling procedures developed to study the metabolism of intestinal symbiotic ecosystems in fish reared in their environment. Metabolites in feces were compared, and intestinal contents and feed were annotated based on HSQC and TOCSY using SpinAssign and network analysis. Feces were characterized by species and varied greatly depending on the feeding types. In addition, feces samples demonstrated a response to changes in the time series of feeding. The potential of this approach as a non-invasive inspection technique in aquaculture is suggested.

Comparative metabolomic and ionomic approach for abundant fishes in estuarine environments of Japan.

Environmental metabolomics or ionomics is widely used to characterize the effects of environmental stressors on the health of aquatic organisms. However, most studies have focused on liver and muscle tissues of fish, and little is known about how the other organs are affected by environmental perturbations and effects such as metal pollutants or eutrophication. We examined the metabolic and mineral profiles of three kinds of abundant fishes in estuarine ecosystem, yellowfin goby, urohaze-goby, and juvenile Japanese seabass sampled from Tsurumi River estuary, Japan. Multivariate analyses, including nuclear magnetic resonance-based metabolomics and inductively coupled plasma optical emission spectrometry-based ionomics approaches, revealed that the profiles were clustered according to differences among body tissues rather than differences in body size, sex, and species. The metabolic and mineral profiles of the muscle and fin tissues, respectively, suggest that these tissues are most appropriate for evaluating environmental perturbations. Such analyses will be highly useful in evaluating the environmental variation and diversity in aquatic ecosystems.

Variant cardiovascular regulation in children with postural tachycardia syndrome.

BACKGROUND: Postural tachycardia syndrome (POTS) manifests as marked tachycardia while standing. We noticed two forms of circulatory response to orthostatic stress in POTS. We investigated cardiovascular and autonomic nervous response to orthostatic stress in the two forms. METHODS: We studied 79 patients with POTS and 38 healthy control subjects (Ct). Beat-to-beat blood pressure (BP) and heart rate (HR) were non-invasively and continuously measured in the supine and standing positions. Autonomic nervous function was evaluated on power spectral analysis of HR variability and diastolic BP variability. We divided the subjects into two groups: standing-induced tachycardia (SI group; increase in HR ≥35 beats/min) and supine tachycardia (Su group; standing HR ≥115 beats/min with standing-induced HR increase <35 beats/min). RESULTS: The Su group had higher supine BP and HR compared with the other groups, indicating dominant sympathetic control of the heart in the supine position. While rising, the SI group had a higher increase in HR than the Ct group, indicating excessive withdrawal of vagal tone. The Su group had a smaller increase in HR and a greater decrease of systolic BP and cardiac index by standing compared with the SI group. These results suggest that compensatory mechanisms of sympathetic function during standing failed in the Su group, probably because of exhaustion by the nearly maximum effort to generate sympathetic drive even in the supine position with low central blood volume. CONCLUSION: There is a difference between the two types of POTS, in the balance of resting autonomic function and hemodynamic response to standing.

Emission Reduction of Fuel-Staged Aircraft Engine Combustor Using an Additional Premixed Fuel Nozzle.

The Japan Aerospace Exploration Agency (JAXA) is conducting research and development on aircraft engine technologies to reduce environmental impact for the Technology Development Project for Clean Engines (TechCLEAN). As a part of the project, combustion technologies have been developed with an aggressive target that is an 80% reduction over the NOx threshold of the International Civil Aviation Organization (ICAO) Committee on Aviation Environmental Protection (CAEP)/4 standard. A staged fuel nozzle with a pilot mixer and a main mixer was developed and tested using a single-sector combustor under the target engine's landing and takeoff (LTO) cycle conditions with a rated output of 40 kN and an overall pressure ratio of 25.8. The test results showed a 77% reduction over the CAEP/4 NOx standard. However, the reduction in smoke at thrust conditions higher than the 30% MTO condition and of CO emission at thrust conditions lower than the 85% MTO condition are necessary. In the present study, an additional fuel burner was designed and tested with the staged fuel nozzle in a single-sector combustor to control emissions. The test results show that the combustor enables an 82% reduction in NOx emissions relative to the ICAO CAEP/4 standard and a drastic reduction in smoke and CO emissions.

Concentration of metabolites from low-density planktonic communities for environmental metabolomics using nuclear magnetic resonance spectroscopy.

Environmental metabolomics is an emerging field that is promoting new understanding in how organisms respond to and interact with the environment and each other at the biochemical level. Nuclear magnetic resonance (NMR) spectroscopy is one of several technologies, including gas chromatography-mass spectrometry (GC-MS), with considerable promise for such studies. Advantages of NMR are that it is suitable for untargeted analyses, provides structural information and spectra can be queried in quantitative and statistical manners against recently available databases of individual metabolite spectra. In addition, NMR spectral data can be combined with data from other omics levels (e.g. transcriptomics, genomics) to provide a more comprehensive understanding of the physiological responses of taxa to each other and the environment. However, NMR is less sensitive than other metabolomic techniques, making it difficult to apply to natural microbial systems where sample populations can be low-density and metabolite concentrations low compared to metabolites from well-defined and readily extractable sources such as whole tissues, biofluids or cell-cultures. Consequently, the few direct environmental metabolomic studies of microbes performed to date have been limited to culture-based or easily defined high-density ecosystems such as host-symbiont systems, constructed co-cultures or manipulations of the gut environment where stable isotope labeling can be additionally used to enhance NMR signals. Methods that facilitate the concentration and collection of environmental metabolites at concentrations suitable for NMR are lacking. Since recent attention has been given to the environmental metabolomics of organisms within the aquatic environment, where much of the energy and material flow is mediated by the planktonic community, we have developed a method for the concentration and extraction of whole-community metabolites from planktonic microbial systems by filtration. Commercially available hydrophilic poly-1,1-difluoroethene (PVDF) filters are specially treated to completely remove extractables, which can otherwise appear as contaminants in subsequent analyses. These treated filters are then used to filter environmental or experimental samples of interest. Filters containing the wet sample material are lyophilized and aqueous-soluble metabolites are extracted directly for conventional NMR spectroscopy using a standardized potassium phosphate extraction buffer. Data derived from these methods can be analyzed statistically to identify meaningful patterns, or integrated with other omics levels for comprehensive understanding of community and ecosystem function.

Expression and functions of myo-inositol monophosphatase family genes in seed development of Arabidopsis.

Myo-inositol monophosphatase (IMP) catalyzes the dephosphorylation of myo-inositol 3-phosphate in the last step of myo-inositol biosynthesis. IMP is also important in phosphate metabolism and is required for the biosynthesis of cell wall polysaccharides, phytic acid, and phosphatidylinositol. In Arabidopsis, IMP is encoded by VTC4. There are, however, two additional IMP candidate genes, IMPL1 and IMPL2, which have not yet been elucidated. In our genetic studies of Arabidopsis IMP genes, only the loss-of-function mutant impl2 showed embryonic lethality at the globular stage. All IMP genes were expressed in a similar manner both in the vegetative and reproductive organs. In developing seeds, expression of IMP genes was not coupled with the expression of the genes encoding myo-inositol phosphate synthases, which supply the substrate for IMPs in the de novo synthesis pathway. Instead, expression of IMP genes was correlated with expression of the gene for myo-inositol polyphosphate 1-phosphatase (SAL1), which is involved in the myo-inositol salvage pathway, suggesting a possible salvage pathway role in seed development. Moreover, the partial rescue of the impl2 phenotype by histidine application implies that IMPL2 is also involved in histidine biosynthesis during embryo development.

[Relation between television commercial of alcoholic beverage and alcoholism].

BACKGROUND AND PURPOSE: Alcoholism is a disease that greatly ruins body mental health, family's health, and a social property. Moreover, it is a disease that a few drinking are connected with the danger of the relapse because there is a control trouble of the drinking desire. The purpose of this survey is to clarify the relation between television commercial of alcoholic beverage (CM) and alcoholism. METHODS: Questionnaire survey on CM and the drinking desire of alcoholism was carried out. Participants were 104 abstinent patients (AP) and 221 healthy control subjects (HCS). HCS were ruled out alcohol dependence syndrome range by Alcohol Use Disorders Identification Test. Statistical analysis was performed using Chi-square and Fisher's exact tests as well as adjusted residuals to compare AP and HCS. In addition, AP was analyzed the relationship between period of abstinence and CM. RESULTS: The average period of abstenence from drinking was 3.38 +/- 1.55 years. AP had the experience of receiving stimulation to the drinking desire by CM. AP had the unpleasantness to the CM. Also, they hoped to discontinue CM, they felt the unpleasantness when they watched CM. Generally, three years are considered to be a stability period after abstains from drinking. Thirty-seven% of AP with 3 years and 27% of AP with 5 years answered "It is very which question about "I want to drink alcohol when I watched CM of alcohol beverage". CONCLUSIONS: It was suspected the CM stimulation was a risk element of an external trigger of the drinking desire, and AP had significantly felt "unpleasant" and hoped that "Discontinuance of CM". It was suggested that it is necessary to reconsider the CM stimulation from the viewpoint of relapse prevention of AP.

Ethylene and salicylic acid control glutathione biosynthesis in ozone-exposed Arabidopsis thaliana.

Ozone produces reactive oxygen species and induces the synthesis of phytohormones, including ethylene and salicylic acid. These phytohormones act as signal molecules that enhance cell death in response to ozone exposure. However, some studies have shown that ethylene and salicylic acid can instead decrease the magnitude of ozone-induced cell death. Therefore, we studied the defensive roles of ethylene and salicylic acid against ozone. Unlike the wild-type, Col-0, Arabidopsis mutants deficient in ethylene signaling (ein2) or salicylic acid biosynthesis (sid2) generated high levels of superoxide and exhibited visible leaf injury, indicating that ethylene and salicylic acid can reduce ozone damage. Macroarray analysis suggested that the ethylene and salicylic acid defects influenced glutathione (GSH) metabolism. Increases in the reduced form of GSH occurred in Col-0 6 h after ozone exposure, but little GSH was detected in ein2 and sid2 mutants, suggesting that GSH levels were affected by ethylene or salicylic acid signaling. We performed gene expression analysis by real-time polymerase chain reaction using genes involved in GSH metabolism. Induction of gamma-glutamylcysteine synthetase (GSH1), glutathione synthetase (GSH2), and glutathione reductase 1 (GR1) expression occurred normally in Col-0, but at much lower levels in ein2 and sid2. Enzymatic activities of GSH1 and GSH2 in ein2 and sid2 were significantly lower than in Col-0. Moreover, ozone-induced leaf damage observed in ein2 and sid2 was mitigated by artificial elevation of GSH content. Our results suggest that ethylene and salicylic acid protect against ozone-induced leaf injury by increasing de novo biosynthesis of GSH.