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Exploring Work-Related Stress and Coping Strategies among Omani Nurses Working in Tertiary Governmental Hospitals at Muscat: A Cross-Sectional Study
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作者 Safiya Al-Yaqoubi 《Open Journal of Nursing》 2023年第6期368-385,共18页
Introduction: Work-related stress has become a global issue in the nursing workplace, with about 9.20% - 68.0% of nurses globally experiencing stress. Conversely, work-related stress ranges between 20% and 40% in nurs... Introduction: Work-related stress has become a global issue in the nursing workplace, with about 9.20% - 68.0% of nurses globally experiencing stress. Conversely, work-related stress ranges between 20% and 40% in nursing. Other researchers noted that 35.1% of nurses globally experienced elevated stress levels. Stress can damage well-being and lead to coping, which can, directly and indirectly, improve well-being through a perceived state. Nurses need coping mechanisms to manage their stress levels and maintain stability. Coping mechanisms can vary greatly depending on a nurse’s culture and background. Numerous findings indicate that managing stress is more critical than the cause of stress and that the more successful a stress-management approach, the less damage stress brings. Objective: In response to this, it is necessary to explore Omani nurses’ stress level and their coping strategies working in tertiary governmental hospitals in Muscat. Methods: The sample size for this study was 383 Omani nurses, with a 100% response rate. This study used a descriptive cross-sectional design from 15 October 2020 to 30 November 2020. Samples were selected through proportionate population sampling (PPS) from the five selected tertiary hospitals. Data were collected by self-administered questionnaires using a perceived stress scale and Ways of Coping. A simple random sample within a stratum (each hospital admitting ward) was done to identify the study participants. The sample size for this study was 383 Omani nurses, with a 100% response rate. Results: About 83.3% of participants had a moderate perceived level of stress with an overall mean perceived stress level of 18.46 ± 4.52. The most common sources of perceived stress are feeling nervous and “stressed” in the last month (2.30 ± 0.95). According to the ways of coping strategies, nurses seemed to be resorting to more “planful problem” (mean = 11.04) and least was seeking social support (mean = 9.67). Conclusion: This study highlighted the work-related stress level of staff nurses, explored their ways of coping and determined the relationship between work-related stress levels and methods of coping. The key finding of this study was that the frequency of stress reported by nurses was high enough to suggest that their stress levels were significant, given the demanding nature of their profession that requires maximum attention. Additionally, nurses seemed to resort to more planful problem-solving mechanisms to deal with their stressful situations than other coping strategies. 展开更多
关键词 stress Level Work-related stress Coping Strategies
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Molecular Cloning and Characterization of Three Novel Genes Related to Fatty Acid Degradation and Their Responses to Abiotic Stresses in Gossypium hirsutum L. 被引量:1
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作者 DONG Jia WEI Li-bin +1 位作者 HU Yan GUO Wang-zhen 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2013年第4期582-588,共7页
Fatty acid metabolism is responsible not only for oilseed metabolism but also for plant responses to abiotic stresses. In this study, three novel genes related to fatty acid degradation designated GhACX, Gh4CL, and Gh... Fatty acid metabolism is responsible not only for oilseed metabolism but also for plant responses to abiotic stresses. In this study, three novel genes related to fatty acid degradation designated GhACX, Gh4CL, and GhMFP, respectively, were isolated from Gossypium hirsutum acc. TM-1. The phylogenetic analysis revealed that amino acid sequences of GhACXand GhMFP have the highest homology with those from Vitis vinifera, and Gh4CL has a closer genetic relationship with that from Camellia sinensis. Tissue- and organ-specific analysis showed that the three genes expressed widely in all the tested tissues, including ovules and fiber at different developing stages, with expressed preferentially in some organs. Among them, GhACX showed the most abundant transcripts in seeds at 25 d post anthesis (DPA), however, GhMFP and Gh4CL have the strongest expression level in ovules on the day of anthesis. Based on real-time quantitative RT-PCR, the three genes were differentially regulated when induced under wounding, methyl jasmonate (MeJA), cold, and abscisic acid (ABA) treatments. The characterization and expression pattern of three novel fatty acid degradation related genes will aid both to understand the roles of fatty acid degradation related genes as precursor in stress stimuli and to elucidate the physiological function in cotton oilseed metabolism. 展开更多
关键词 genes related to fatty acid degradation molecular cloning expression analysis abiotic stress cotton( Gossypium hirsutum L.)
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Impacts of high temperature,relative air humidity,and vapor pressure deficit on the seed set of contrasting maize genotypes during flowering
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作者 Xin Dong Baole Li +8 位作者 Zhenzhen Yan Ling Guan Shoubing Huang Shujun Li Zhiyun Qi Ling Tang Honglin Tian Zhongjun Fu Hua Yang 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第9期2955-2969,共15页
Heat stress is a major constraint to current and future maize production at the global scale.Male and female reproductive organs both play major roles in increasing seed set under heat stress at flowering,but their re... Heat stress is a major constraint to current and future maize production at the global scale.Male and female reproductive organs both play major roles in increasing seed set under heat stress at flowering,but their relative contributions to seed set are unclear.In this study,a 2-year field experiment including three sowing dates in each year and 20 inbred lines was conducted.Seed set,kernel number per ear,and grain yield were all reduced by more than 80%in the third sowing dates compared to the first sowing dates.Pollen viability,silk emergence ratio,and anthesis-silking interval were the key determinants of seed set under heat stress;and their correlation coefficients were 0.89^(***),0.65^(***),and-0.72^(***),respectively.Vapor pressure deficit(VPD)and relative air humidity(RH)both had significant correlations with pollen viability and the silk emergence ratio.High RH can alleviate the impacts of heat on maize seed set by maintaining high pollen viability and a high silk emergence ratio.Under a warming climate from 2020 to 2050,VPD will decrease due to the increased RH.Based on their pollen viability and silk emergence ratios,the 20 genotypes fell into four different groups.The group with high pollen viability and a high silk emergence ratio performed better under heat stress,and their performance can be further improved by combining the improved flowering pattern traits. 展开更多
关键词 MAIZE pollen viability silk emergence heat stress relative humidity
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The Relationship between Post-Traumatic Stress Disorder and Self-Esteem along with the Importance of Support for Children
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作者 Fumihiro Omasu Yukino Hotta +1 位作者 Mai Watanabe Tomomi Yoshioka 《Open Journal of Preventive Medicine》 2018年第4期95-101,共7页
Post-Traumatic Stress Disorder (PTSD) is widely known in our society. The symptoms of PTSD are particularly believed to occur predominantly in children. We believe that Yogo teachers, who play a role in maintaining an... Post-Traumatic Stress Disorder (PTSD) is widely known in our society. The symptoms of PTSD are particularly believed to occur predominantly in children. We believe that Yogo teachers, who play a role in maintaining and promoting the health of children, are expected to provide appropriate support for children with a tendency for PTSD. In this study, we investigated the tendency for PTSD in students at University, as well as self-esteem related to depression and anxiety. Furthermore, we clarified the relationship between PTSD and self-esteem and examined the support provided by Yogo teachers. As a result, it was found that the higher the tendency for PTSD, the lower the self-esteem. We believe that the onset of PTSD causes a decline in memory ability and attentional function, which interferes with one’s life and leads to self-denial, resulting in a decline in self-esteem among those with a high tendency for PTSD. These results suggest that Yogo teachers should provide support to prevent the onset of PTSD in child students due to accidents, incidents, natural disasters, etc., as well as support to prevent the decline in self-esteem associated with the onset of PTSD. 展开更多
关键词 POST-TRAUMATIC stress DISORDER self-esteem University STUDENT Yogo TEACHER
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Sequential Mediating Effect of Proactive Coping and Perceived Stress in the Relationships between Self-Esteem Stability and Life Satisfaction
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作者 Seungju Hyun 《International Journal of Mental Health Promotion》 2022年第3期425-437,共13页
While the effect of self-esteem stability on life satisfaction is widely verified,it is not very known how coping strategies explain this relationship.The present study focused on proactive coping,a preliminary step t... While the effect of self-esteem stability on life satisfaction is widely verified,it is not very known how coping strategies explain this relationship.The present study focused on proactive coping,a preliminary step to minimize the impact of expected stressors,and a process of recognizing stressful events as challenges and actively managing them.Specifically,this study(N=280)examined whether proactive coping and perceived stress mediated the relationship between self-esteem stability and life satisfaction in a sequential manner.The results indicate that proactive coping and perceived stress sequentially mediated the relationship between self-esteem stability and life satisfaction,respectively.This demonstrates that proactive coping and perceived stress are factors that link self-esteem and life satisfaction.However,there was no direct effect between self-esteem and life satisfaction.These findings suggest the need to consider combining proactive coping interventions to increase the effectiveness of a self-esteem stability promotion program.The practical implications and suggestions for future research are also discussed. 展开更多
关键词 self-esteem stability proactive coping perceived stress life satisfaction
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The relationship between psychological distress with salivary <i>α</i>-amylase and stress related symptoms among breast cancer survivors 被引量:1
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作者 H. W. Yong H. Zailina +3 位作者 J. O. Zubaidah M. Saidi H. Y. Yong M. S. Zalilah 《Health》 2013年第4期811-816,共6页
Background and Aims: This study examined the stress levels, the stressors and biomarker such as Alpha (α)-Amylase enzyme which is secreted under distress conditions. The aim was to determine the relationship between ... Background and Aims: This study examined the stress levels, the stressors and biomarker such as Alpha (α)-Amylase enzyme which is secreted under distress conditions. The aim was to determine the relationship between these three variables. Methods: The study respondents were made up of cancer outpatients from 3 hospitals namely the Hospital Kuala Lumpur, Seberang Jaya and Johor Baru, Pantai Ipoh and Putrajaya. The Personal Stress Inventory (PSI) questionnaire was used to identify stressors, while the Hospital Anxiety and Depression Scale (HADS) were used to determine the psychological distress levels. The Salimentary Oral Swab (SOS) Technique was used to collect the saliva and then the Salivary α-Amylase Assay Kit was used to analyse for α amylase. Results: The majority of respondents were stressed due to their sensitive emotion and nervousness in their daily lives (68.7%), they had poor memory and short attention spans of carrying out job tasks (67.3%) as well as they were emotionally depressed (65.3%). Their poor memory and short attention span (p = 0.037), heavy work load and poor task delivery (p = 0.008) were predictors for distress using HADS. The salivary α-amylase concentration was significantly related to the stress levels (p = 0.002). Conclusion: Breast cancer respondents with musculoskeletal system related symptoms, with heavy work load and poor task delivery, as well as had poor memory and short attention span were at higher risk of experiencing psychological distress. The salivary α-amylase which had significant relationships with psychological distress was therefore, a potential biological indicator for distress, while the musculoskeletal system related symptoms from the PSI questionnaire were predictors for distress. 展开更多
关键词 Breast Cancer Survivors SALIVARY Α-AMYLASE stress-related Symptoms Distress
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Illness Perception in Gestational Trophoblastic Disease Patients: How Mental Representations Affect Anxiety, Depression, and Infertility-Related Stress 被引量:1
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作者 Letizia Carnelli Valentina E. Di Mattei +7 位作者 Martina Mazzetti Martina Bernardi Rossella Di Pierro Alice Bergamini Francesca Pella Giorgia Mangili Lucio Sarno Massimo Candiani 《Open Journal of Medical Psychology》 2017年第1期1-15,共15页
Gestational Trophoblastic Disease encompasses a group of pregnancy-related disorders that derive from the placenta. Taking Leventhal’s Common Sense Model as a starting point, this study aims to investigate how illnes... Gestational Trophoblastic Disease encompasses a group of pregnancy-related disorders that derive from the placenta. Taking Leventhal’s Common Sense Model as a starting point, this study aims to investigate how illness perception could influence patients’ psychological adaptation to these rare diseases. Thirty-seven women completed: the Illness Perception Questionnaire-Revised, the Beck Depression Inventory Short Form, the State-Trait Anxiety Inventory, and the Fertility Problem Inventory. Results show that the perception of severe illness consequences significantly predicts the level of anxiety patients reported at the time of questionnaire completion. Furthermore, mental representations of illness present a significant association with infertility-related stress. Specifically, the belief in the efficacy of the treatment results in fewer feelings of discomfort and isolation from family and social context due to infertility-related problems. Since patients’ illness perception was found to have a specific impact on both anxiety and infertility-related stress, this variable should be considered in the planning of a clinical intervention. 展开更多
关键词 GESTATIONAL Trophoblastic Disease Illness Perception ANXIETY DEPRESSION Infertility-related stress
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THE EXPERIMENTAL STUDY OF STRESS-RELATED PATHOLOGICAL CHANGES IN CEREBRAL VENOUS BLOOD FLOW IN NEWBORN RATS ASSESSED BY DOCT
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作者 OXANA V.SEMYACHKINA-GLUSHKOVSKAYA VLADISLAV V.LYCHAGOV +8 位作者 OLGA A.BIBIKOVA IGOR A.SEMYACHKIN-GLUSHKOVSKIY SERGEY S.SINDEEV EKATERINAM.ZINCHENKO MOHHANAD M.KASSIM AL-FATLE FATEMA ALI AL HASSANI LEITH MARIA V.ULANOVA VALERY V.TUCHIN 《Journal of Innovative Optical Health Sciences》 SCIE EI CAS 2013年第3期76-85,共10页
In experiments on newbom rats with stress related intracrani al hemorhage(ICH)using Doppler optical coberence tomognaphy(DOCT)we have shown that latent stage of ICH(4 h after stress)is characterized by decrease of ven... In experiments on newbom rats with stress related intracrani al hemorhage(ICH)using Doppler optical coberence tomognaphy(DOCT)we have shown that latent stage of ICH(4 h after stress)is characterized by decrease of venous blood outflow and the loss of sensitivity of sagittal vein to vasoconstrictor ffect of adrenaline.The incidence of ICH(24 h after stress)was accompanied by progressi on of early pathological changes in cerebral venous blood flow(CVBF)and development of venous insufficiency.Taking into consideration of this fact,we suggest that the suppression of CVBF related to the severity to the deleterious effect of stress on the brain hemodynamics in newborn rats.These facts allow us to conclude that the venous insufficiency with the loss of vasoconstrictor response to adrenaline is an informative and sensitive component of pattern of CVBF that can be important diagnostic criteria of risk of ICH development in newborns. 展开更多
关键词 Doppler optical coherence tomography stress related intracnanial hemorthage cerebral venous blood flow ADRENALINE
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Heat Stress Related Gene Expression in Gossypium hirsutum L.
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作者 DEMIREL Ufuk GR M Atilla +1 位作者 KARAKU Mehmet MEMON Abdul Rezaque 《棉花学报》 CSCD 北大核心 2008年第S1期38-,共1页
Abiotic stress is a major limiting factor to crop productivity,and heat stress is one of the important elements for reduced crop production.Plants respond to heat stress at molecular and cellular levels as well as phy... Abiotic stress is a major limiting factor to crop productivity,and heat stress is one of the important elements for reduced crop production.Plants respond to heat stress at molecular and cellular levels as well as physiological level.Heat stress alters expression patterns of numerous genes in plants. 展开更多
关键词 ESTS Heat stress related Gene Expression in Gossypium hirsutum L
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The Wheat Pathogenesis Related Protein (TdPR1.2) Ensures Contrasting Behaviors to <i>E. coli</i>Transformant Cells under Stress Conditions
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作者 Mouna Ghorbel Ikram Zribi +3 位作者 Najla Haddaji Malek Besbes Nouha Bouali Faiçal Brini 《Advances in Microbiology》 2021年第9期453-468,共16页
The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metabolism in response to biotic and abiotic stresses. The wheat TdPR1.2 has been previously isolated and characterized. Here we... The pathogenesis-related proteins 1 (PR-1) gene family play important roles in the plant metabolism in response to biotic and abiotic stresses. The wheat TdPR1.2 has been previously isolated and characterized. Here we showed by bio-informatic analysis that TdPR1.2 contains six cysteine residues that are conserved between all PR-1 proteins tested. Using ScanProsite tool, we found that TdPR1.2 structure has a CRISP family signature 1 and 2 located at the C-terminal part of the protein. Those two domains are conserved in many identified PR1.2 proteins in plants. Moreover, SignalIP-5.0 analysis revealed that TdPR1.2 contains a putative signal peptide formed by 25 amino acids at the N-terminal extremity. The presence of this signal peptide suggested that the mature proteins will be secreted after the cleavage of the signal sequence. Further, we investigate the role of the TdPR1.2 proteins in the growth of <i>Escherichia coli</i> transformants cells under different abiotic stresses. Our results showed that the full-length form of TdPR1.2 enhanced tolerance of <i>E. coli</i> against salt and osmotic stress but not to KCl. Moreover, TdPR1.2 protein confers bacterial tolerance to heavy metals in solid and liquid mediums. Based on these results, we suggest that the TdPR1.2 protein could play an important role in response to abiotic stress conditions. 展开更多
关键词 Abiotic stress Bioinformatic Analysis Durum Wheat E. coli Growth Inhibition Pathogen related Proteins Protein Expression
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Effects of Ticagrelor on oxidative stress, coagulation function, platelet function and related factors in patients with coronary artery disease undergoing interventional therapy
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作者 Shan Mao Yu Li +1 位作者 Zhi-Xiao Wang Xiang-Hong Luo 《Journal of Hainan Medical University》 2019年第6期24-27,共4页
Objective: To explore the effects of Ticagrelor on oxidative stress, coagulation function, platelet function and related factors in patients with coronary artery disease undergoing interventional therapy. Methods: A t... Objective: To explore the effects of Ticagrelor on oxidative stress, coagulation function, platelet function and related factors in patients with coronary artery disease undergoing interventional therapy. Methods: A total of 140 patients with coronary artery disease who underwent percutaneous coronary intervention in our hospital from October 2016 to March 2018 were selected as the study subjects and were divided into control group (70 cases) and observation group (70 cases) by drawing lots. Both groups were treated with symptomatic routine therapy before operation. On this basis, the control group was treated with clopidogrel before operation, and the observation group was treated with Ticagrelor before operation on the basis of routine treatment. The changes of oxidative stress, coagulation index, platelet function and related factors were compared between the two groups before and after treatment. Results: Before treatment, there were no significant differences in oxidative stress factors, coagulation parameters, platelet parameters and related factors factors between the two groups. After treatment, the levels of MDA, MPAR, VEGF and MMP-9 in the two groups were lower than those before treatment, while the levels of SOD, APTT, TT and PT were higher than those before treatment;and the levels of MDA, MPAR, VEGF, MMP-9, APTT and PT in the observation group were significantly lower than those in the control group after treatment, while the levels fo SOD, TT and IPA in the observation group were significantly higher than those in the control group. Conclusions: Ticagrelor can better reduce oxidative stress injury, improve coagulation function and coronary stenosis, and inhibit platelet aggregation in patients with coronary heart disease undergoing PCI than clopidogrel. It has clinical popularization significance. 展开更多
关键词 INTERVENTIONAL therapy for coronary heart disease Ticagrelor Oxidative stress COAGULATION FUNCTION PLATELET FUNCTION related factors
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Effects of Xuefu Zhuyu Decoction combined with conventional therapy on inflammatory response, oxidative stress, endothelium and related factors in patients with acute cerebral infarction
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作者 Feng Chen Xi Wu +2 位作者 Ying-Tao Mu Tao-Tao Xu Ren-Bin Liu 《Journal of Hainan Medical University》 2019年第10期40-43,共4页
Objective: To explore the effects of Xuefu Zhuyu Decoction combined with conventional therapy on inflammatory response, oxidative stress, endothelium and related factors in patients with acute cerebral infarction. Met... Objective: To explore the effects of Xuefu Zhuyu Decoction combined with conventional therapy on inflammatory response, oxidative stress, endothelium and related factors in patients with acute cerebral infarction. Methods: A total of 162 patients with acute cerebral infarction admitted to our hospital from November 2016 to January 1818 were selected as subjects. According to the random sampling method, the subjects were divided into 81 cases in the control group and 81 cases in the observation group. The control group was treated with conventional intracranial pressure, anticoagulation, anti-oxidation and lipid-lowering treatment. The observation group was treated with Xuefu Zhuyu Decoction on the basis of the control group. The changes of inflammatory response, oxidative stress, endothelium and related factors were compared and analyzed. Results:Before treatment, the levels of TNF-α, CRP, SOD, MDA, AOPPS, NO, ET-1, MMP-9, PAF and IGF-1 in the two groups were not significantly different, and there was no statistical significance. After treatment, the levels of TNF-α and CRP in the two groups were significantly lower than those before treatment, and the levels of TNF-α and CRP in the observation group were significantly lower than control group;the levels of MDA and AOPPS in the two groups were significantly lower than those before treatment, while the level of SOD was significantly higher than before treatment, and the levels of MDA and AOPPS in the observation group were significantly lower than control group, while the level of SOD was significantly higher. In the control group;the level of ET-1 in the two groups was significantly lower than that before treatment, while the level of NO was significantly higher than that before the treatment, and in the observation group the level of ET-1 was significantly lower than the control group, while the level of NO was significantly higher. In the control group;the levels of MMP-9 and PAF in the two groups were significantly lower than those before treatment, while the level of IGF-1 was significantly higher than before treatment, and the levels of MMP-9 and PAF in the observation group were significantly lower than control group, while the level of IGF-1 was significantly higher than control group. Conclusions: Xuefu Zhuyu Decoction combined with conventional treatment of acute cerebral infarction can effectively reduce inflammation and oxidative stress, improve vascular endothelial function and nerve function, and significantly reduce the degree of brain injury, which has clinical significance. 展开更多
关键词 Xuefu Zhuyu DECOCTION ROUTINE treatment Acute CEREBRAL INFARCTION Inflammatory response Oxidative stress ENDOTHELIUM related factors
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Variation in Expression of <i>Sub</i>1 Gene and Association with Submergence Stress Related Traits in Advance Rice (<i>Oryza sativa</i>L.) Genotypes as a Tool of Climate Change Adaptation
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作者 Zulqarnain Haider Muhammad Akhter +1 位作者 Abid Mahmood Usman Saleem 《American Journal of Climate Change》 2018年第2期171-186,共16页
Floods have now become most detrimental natural catastrophe worldwide due to radical climatic fluxes. Therefore, there is a dire necessity to develop a high yielding rice lines to deal with this scenario. For this pur... Floods have now become most detrimental natural catastrophe worldwide due to radical climatic fluxes. Therefore, there is a dire necessity to develop a high yielding rice lines to deal with this scenario. For this purpose, a large scale experiment was conducted including one hundred and fifteen (115) rice genotypes having SUB1 gene imported from International Rice Research Institute (IRRI) Philippines, six local cultivars/approved varieties and three high yielding rice varieties i.e. Sabitri, IR6 and NSICRC222 being used as potential varieties in different countries of Asia as susceptible check and IR64-SUB1 as tolerant check. The genotypic screening was performed using two PCR-based DNA markers i.e. ART5 and SC3. Phenotypic screening was conducted in a natural pond to assess the interaction of SUB1 gene in natural stagnant flood water as well as the suitability of introgression of SUB1 gene into approved varieties and elite rice lines. The genotypes were assessed in terms of plant survival percentage, submergence tolerance index, physical condition, stem elongation, number of grains per panicle, thousand grain weight, grain yields and deviations in these traits after submergence stress. The PCR results suggested that both the primers ART5 and SC3 may be used as potential PCR-based markers for molecular screening of rice genotypes for SUB1 QTL. Furthermore, it confirmed the presence of SUB1 gene in all the lines imported from IRRI, while it was absent in all the local cultivars studied. All the genotypes with submergence tolerant gene (SUB1) showed significantly greater tolerance level in submergence stress of 14 days, as compared to other local cultivars/varieties, authenticating the effectiveness of SUB1QTL in conferring submergence tolerance. Significantly different performances of all the SUB1 genotypes in terms of all the studied traits indicate high Genotypic and Genotypic Environment Interaction (GEI) of SUB1QTL. Employment of SUB1 lines such as R105479:149-18, IR64-SUB1 and Rl05469:81-22-3 in breeding programs for developing flood tolerant rice varieties might further upsurge rice yields in flash flood areas. Correlation analysis revealed that plant survival percentage after submergence, reduced stem elongation during submergence and submergence tolerance index are very important traits for developing submergence tolerant lines. 展开更多
关键词 Oryza SATIVA L. Sub1 QTL Floods Climate Change PHENOTYPIC EXPRESSION ASSOCIATION Analysis stress related Traits
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Effect of flow stress—strain relation on forming limit of 5754O aluminum alloy 被引量:3
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作者 王海波 万敏 阎昱 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2370-2378,共9页
A modified Swift type flow stress—strain relation was presented in order to describe the uniaxial tension test curve reasonably. The FLD-strain (forming limit diagram made up of limit strain) of 5754O aluminum allo... A modified Swift type flow stress—strain relation was presented in order to describe the uniaxial tension test curve reasonably. The FLD-strain (forming limit diagram made up of limit strain) of 5754O aluminum alloy sheet was calculated based on the two flow stress—strain relations using Yld2000-2d yield function. By comparing the theoretical and experimental results, it is found that the calculated FLD-strain based on the modified Swift flow stress—strain relation can reasonably describe the experimental results. However, though the common Voce flow stress—strain relation can describe the deformation behavior during homogenous deformation phase accurately, the FLD-strain calculated based on it is obviously lower than the experimental result. It is concluded that the higher the hardening rate of sheet metal is, the higher the forming limit is. A method for determining the reasonable flow stress—strain relation is recommended for describing the material behavior during inhomogenous phase and the forming limit of sheet metal. 展开更多
关键词 aluminum alloy forming limit sheet metal flow stress—strain relation inhomogenous deformation
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Effect of Relative Stress on Post-Peak Uniaxial Compression Fracture Energy of Concrete 被引量:4
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作者 王学滨 PANYi-shan 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2003年第4期89-92,共4页
Fracture energy in strain softening regime was investigated analytically by considering microstructures interaction and interplay.Based on gradient-dependent plasticity, the thickness of localized band was determined ... Fracture energy in strain softening regime was investigated analytically by considering microstructures interaction and interplay.Based on gradient-dependent plasticity, the thickness of localized band was determined completely and strictly by characteristic length in relation to average grain diameter.After obtaining the plastic shear displacement of the band,the formula on axial response of concrete was proposed and the analytical post-peak fracture energy was deduced.A comparison between present theoretical results and earlier experimental results was carried out and the analytical result is reasonable and has a plausible foundation as considering the localized failure theoretically.Decreasing the relative stress leads to increasing the fracture energy non-linearly.The larger the shear elastic modulus and shear softening modulus,the lower the post-peak fracture energy.A larger fracture energy is caused by a larger thickness of shear band or a larger characteristic length of concrete material.If the inclination angle of the shear band and the compressive strength are not concerned with structural size of specimen,the post-peak fracture energy is size independent. 展开更多
关键词 fracture energy relative stress gradient-dependent plasticity thickness of shear band uniaxial compression characteristic length
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Constitutive relation of weakly anisotropic polycrystal with microstructure and initial stress 被引量:7
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作者 Mojia Huang Hua Zhan Xiuqiao Lin Hai Tang 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2007年第2期183-198,共16页
Man (Nondestr Test Eval 15:191-214, 1999) derived the constitutive relation of a weakly-textured orthorhombic aggregate of cubic crystallites with effects of microstructure and initial stress. In this paper, a comp... Man (Nondestr Test Eval 15:191-214, 1999) derived the constitutive relation of a weakly-textured orthorhombic aggregate of cubic crystallites with effects of microstructure and initial stress. In this paper, a computational expression on the integration ∫SO(3) Q^× D^1m0dg is given. Then, by means of the computational expression, the general constitutive relation of a weakly-textured anisotropic polycrystal with the consideration of microstructure and initial stress is derived. As special cases of our general constitutive relation, two constitutive relations are given for an isotropic polycrystal and a weakly-textured anisotropic aggregate of cubic crystallites. The acoustoelastic tensor of the reference cubic crystal is derived to determine the material constants of the polycrystal. Two examples are given for understanding the physical meaning of the texture coefficients and the constitutive relations. 展开更多
关键词 Generalconstitutive relation of weakly-textured polycrystal .Microstructure Initial stress .Cubic crystallites
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VISCOELASTIC CONSTITUTIVE MODEL RELATED TO DEFORMATION OF INSECT WING UNDER LOADING IN FLAPPING MOTION 被引量:1
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作者 鲍麟 胡劲松 +3 位作者 余永亮 程鹏 续伯钦 童秉纲 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2006年第6期741-748,共8页
Flexible insect wings deform passively under the periodic loading during flapping flight. The wing flexibility is considered as one of the specific mechanisms on improving insect flight performance. The constitutive r... Flexible insect wings deform passively under the periodic loading during flapping flight. The wing flexibility is considered as one of the specific mechanisms on improving insect flight performance. The constitutive relation of the insect wing material plays a key role on the wing deformation, but has not been clearly understood yet. A viscoelastic constitutive relation model was established based on the stress relaxation ex- periment of a dragonfly wing (in vitro). This model was examined by the finite element analysis of the dynamic deformation response for a model insect wing under the action of the periodical inertial force in flapping. It is revealed that the viscoelastic constitutive relation is rational to characterize the biomaterial property of insect wings in contrast to the elastic one. The amplitude and form of the passive viscoelastic deformation of the wing is evidently dependent on the viscous parameters in the constitutive relation. 展开更多
关键词 constitutive relation VISCOELASTICITY stress relaxation finite element analysis insect wing passive deformation
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The effects of an exercise program on health-related quality of life in postpartum mothers: A randomized controlled trial 被引量:1
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作者 Megumi Haruna Etsuko Watanabe +5 位作者 Masayo Matsuzaki Erika Ota Mie Shiraishi Ryoko Murayama Mikako Yoshida SeonAe Yeo 《Health》 2013年第3期432-439,共8页
Background and Objective: There is controversy on the psychological effects of postpartum exercise. The study aimed to evaluate the effectiveness of a postpartum exercise program on health-related quality of life and ... Background and Objective: There is controversy on the psychological effects of postpartum exercise. The study aimed to evaluate the effectiveness of a postpartum exercise program on health-related quality of life and psychological well-being. Methods: We conducted a randomized controlled trial in Tokyo, Japan. The intervention groups participated in ball-exercise classes (weekly exercise of 90 minutes for four weeks) at three months postpartum. The exercise class included the following: 1) greeting and warm-up;2) aerobic exercise involving bouncing on an exercise ball 55 or 65 cm in diameter;3) rest and self-introduction;4) stretching and cooling down. The primary outcome measure was health-related Quality of Life (QOL) assessed using the MOS Short-Form 36-Item Health Survey (SF-36v2). The secondary outcome measures were Rosenberg Self-Esteem Scale (RSES) and Edinburgh Postnatal Depression Scale (EPDS) scores. The intervention group was compared to the control group at four months postpartum. Results: Of the 120 women screened, 110 women met the study criteria. Nine could not be included and the remaining 101 were allocated randomly into intervention and control groups (50 and 51 participants respectively). Analysis of covariance adjusting for baseline values indicated that the SF36 subscales of physical functioning (p = 0.018) and vitality (p = 0.016) significantly improved in the intervention group compared to the control group, although there were no significant differences between the groups in the SF36 Physical Component Summary (PCS) and Mental Component Summary (MCS) scores. The RSES increased in the intervention group (p = 0.020) compared to the control group. No significant group differences were observed in EPDS scores. Conclusions: The postpartum exercise class program provided to healthy postpartum women appears to have contributed to promoting health-related QOL and self-esteem. 展开更多
关键词 EXERCISE Health related Quality of Life POSTPARTUM DEPRESSION RANDOMIZED Controlled TRIAL self-esteem
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Anti-apoptotic treatment in mouse models of age-related hearing loss 被引量:4
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作者 Fengchan Han Oumei Wang Quanxiang Cai 《Journal of Otology》 CSCD 2016年第1期7-12,共6页
Age-related hearing loss (AHL), or presbycusis, is the most common neurodegenerative disorder and top communication deficit of the aged population. Genetic predisposition is one of the major factors in the development... Age-related hearing loss (AHL), or presbycusis, is the most common neurodegenerative disorder and top communication deficit of the aged population. Genetic predisposition is one of the major factors in the development of AHL. Generally, AHL is associated with an age-dependent loss of sensory hair cells, spiral ganglion neurons and stria vascularis cells in the inner ear. Although the mechanisms leading to genetic hearing loss are not completely understood, caspase-family proteases function as important signals in the inner ear pathology. It is now accepted that mouse models are the best tools to study the mechanism of genetic hearing loss or AHL. Here, we provide a brief review of recent studies on hearing improvement in mouse models of AHL by anti-apoptotic treatment. 展开更多
关键词 Age-related hearing loss Mouse model APOPTOSIS Oxidative stress
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Effect of Coarse Aggregate Size on and Crack Opening in Normal and Relationship between Stress High Strength Concretes 被引量:4
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作者 Jun ZHANG Qian LIU Lin WANG 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2005年第5期691-700,共10页
Fine and coarse aggregates play an important role in the fracture of concrete. However, quantitative information available on the effect of the coarse aggregate size on the fracture properties of concrete is still lim... Fine and coarse aggregates play an important role in the fracture of concrete. However, quantitative information available on the effect of the coarse aggregate size on the fracture properties of concrete is still limited. In the present paper, the effect of coarse aggregate size (single grade of 5~10, 10~16, 16~20 and 20~25 mm) on stress-crack opening (σ-w) relation in normal and high strength concretes (compressive strength of 40 and 80 MPa, respectively) was studied. The investigation was based on three-point bending tests implemented by fictitious crack analysis. The result shows that coarse aggregate size and cement matrix strength significantly influence the shape of σ-w curve. For a given total aggregate content, in normal strength concrete, smaller size of aggregate leads to a high tensile strength and a sharp stress drop after the peak stress. The smaller the coarse aggregate, the steeper the σ-w curve. By contrast, in high strength concrete, the effect of aggregate size on σ-w relation almost vanishes. A similar σ-w relation is obtained for the concrete except for the case of 20~25 mm coarse aggregate size. The stress drop after the peak stress is more significant for high strength concrete than that for normal strength concrete. Meanwhile, the smaller the coarse aggregate size, the higher the flexural strength. Fracture energy and characteristic length increase with increasing coarse aggregate size in both normal and high strength concretes. 展开更多
关键词 Aggregate size stress-crack opening relation Fracture energy Bending test
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