Enhanced SA and Ca2+ signaling results in PCD-mediated spontaneous leaf necrosis in wheat mutant wsl.

Leaf is the major photosynthesis organ and the key source of wheat (Triticum aestivum L.) grain. Spotted leaf (spl) mutant is a kind of leaf lesion mimic mutants (LMMs) in plants, which is an ideal material for studying the mechanisms of leaf development. In this study, we report the leaf abnormal development molecular mechanism of a spl mutant named white stripe leaf (wsl) derived from wheat cultivar Guomai 301 (WT). Histochemical observation indicated that the leaf mesophyll cells of the wsl were destroyed in the necrosis regions. To explore the molecular regulatory network of the leaf development in mutant wsl, we employed transcriptome analysis, histochemistry, quantitative real-time PCR (qRT-PCR), and observations of the key metabolites and photosynthesis parameters. Compared to WT, the expressions of the chlorophyll synthesis and photosynthesis-related homeotic genes were repressed; many genes in the WRKY transcription factor (TF) families were highly expressed; the salicylic acid (SA) and Ca2+ signal transductions were enhanced in wsl. Both the chlorophyll contents and the photosynthesis rate were lower in wsl. The contents of SA and reactive oxygen species (ROS) were significantly higher, and the leaf rust resistance was enhanced in wsl. Based on the experimental data, a primary molecular regulatory model for leaf development in wsl was established. The results indicated that the SA accumulation and enhanced Ca2+ signaling led to programmed cell death (PCD), and ultimately resulted in spontaneous leaf necrosis of wsl. These results laid a solid foundation for further research on the molecular mechanism of leaf development in wheat.

Invasiveness-triggered state transition in malignant melanoma cells.

Cancer cells are considered to have high morphological heterogeneity in human melanoma tissue. Here, we report that epithelial cancer cells are dominant in different development stages of human melanoma tissues. The cellular and molecular mechanisms that maintain melanoma cells in the epithelial state are further investigated in the A2058 cell line. We find that micropore (8 µm) transwell invasion, but not superficial migration in the scratch assay, can induce remarkable morphological changes between epithelial and mesenchymal melanoma cells within 4 days. The morphological switch is associated with dynamic changes of epithelial-mesenchymal transition (EMT) hallmarks E-cadherin and vimentin. Further immunoflurencent staining and co-immunoprecipitation assay showed the uncoupling of the M3 muscarinic acetylcholine receptor (mAChR) and the p75 neurotrophin receptor (p75NTR) in epithelial melanoma cells. Specific knockdown of M3 mAChR by small interfering RNA (siRNA) significantly abrogates the transition of spindle-shaped mesenchymal cells to epithelial cells. Collectively, we report a cellular model of invasiveness-triggered state transition (ITST) in which melanoma cell invasion can induce morphological changes between epithelial and mesenchymal cells. ITST is one of the biological basis for maintaining metastatic melanoma cells in the epithelial state. Furthermore, M3 mAChR receptor-mediated ITST provides a novel therapeutic strategy to inhibit the development of malignant melanoma.

Optimal processing scheme for restoration of phase data corrupted by strong decorrelation noise and dislocations.

The presence of speckle noise and dislocations makes phase restoration potentially difficult in quantitative phase imaging and metrology. Unfortunately, there is no appropriate approach to deal with phase data corrupted by high speckle noise and phase dislocations. Usually, processing schemes may deal with low-pass phase filtering, phase unwrapping, or phase inpainting. This paper discusses the efficient processing to deal with noisy phase maps corrupted with phase dislocations. Six processing schemes, combining four operations, are evaluated. The investigation is carried out by realistic numerical simulations in which strong decorrelation phase noise and phase dislocations are generated. As a result, most robust and faster processing is established. The applicability of the optimal scheme is demonstrated through deformation measurement in dental materials.

The Major Factors Causing the Microspore Abortion of Genic Male Sterile Mutant NWMS1 in Wheat (Triticum aestivum L.).

Male sterility is a valuable trait for genetic research and production application of wheat (Triticum aestivum L.). NWMS1, a novel typical genic male sterility mutant, was obtained from Shengnong 1, mutagenized with ethyl methane sulfonate (EMS). Microstructure and ultrastructure observations of the anthers and microspores indicated that the pollen abortion of NWMS1 started at the early uninucleate microspore stage. Pollen grain collapse, plasmolysis, and absent starch grains were the three typical characteristics of the abnormal microspores. The anther transcriptomes of NWMS1 and its wild type Shengnong 1 were compared at the early anther development stage, pollen mother cell meiotic stage, and binucleate microspore stage. Several biological pathways clearly involved in abnormal anther development were identified, including protein processing in endoplasmic reticulum, starch and sucrose metabolism, lipid metabolism, and plant hormone signal transduction. There were 20 key genes involved in the abnormal anther development, screened out by weighted gene co-expression network analysis (WGCNA), including SKP1B, BIP5, KCS11, ADH3, BGLU6, and TIFY10B. The results indicated that the defect in starch and sucrose metabolism was the most important factor causing male sterility in NWMS1. Based on the experimental data, a primary molecular regulation model of abnormal anther and pollen developments in mutant NWMS1 was established. These results laid a solid foundation for further research on the molecular mechanism of wheat male sterility.

Enhanced Senescence Process is the Major Factor Stopping Spike Differentiation of Wheat Mutant ptsd1.

Complete differentiation of the spikes guarantees the final wheat (Triticum aestivum L.) grain yield. A unique wheat mutant that prematurely terminated spike differentiation (ptsd1) was obtained from cultivar Guomai 301 treated with ethyl methane sulfonate (EMS). The molecular mechanism study on ptsd1 showed that the senescence-associated genes (SAGs) were highly expressed, and spike differentiation related homeotic genes were depressed. Cytokinin signal transduction was weakened and ethylene signal transduction was enhanced. The enhanced expression of Ca2+ signal transduction related genes and the accumulation of reactive oxygen species (ROS) caused the upper spikelet cell death. Many genes in the WRKY, NAC and ethylene response factor (ERF) transcription factor (TF) families were highly expressed. Senescence related metabolisms, including macromolecule degradation, nutrient recycling, as well as anthocyanin and lignin biosynthesis, were activated. A conserved tae-miR164 and a novel-miR49 and their target genes were extensively involved in the senescence related biological processes in ptsd1. Overall, the abnormal phytohormone homeostasis, enhanced Ca2+ signaling and activated senescence related metabolisms led to the spikelet primordia absent their typical meristem characteristics, and ultimately resulted in the phenotype of ptsd1.

The miRNA-mRNA Networks Involving Abnormal Energy and Hormone Metabolisms Restrict Tillering in a Wheat Mutant dmc.

Tillers not only determine plant architecture but also influence crop yield. To explore the miRNA regulatory network restraining tiller development in a dwarf-monoculm wheat mutant (dmc) derived from Guomai 301 (wild type, WT), we employed miRNome and transcriptome integrative analysis, real-time qRT-PCR, histochemistry, and determinations of the key metabolites and photosynthesis parameters. A total of 91 differentially expressed miRNAs (DEMs) were identified between dmc and WT. Among them, 40 key DEMs targeted 45 differentially expressed genes (DEGs) including the key DEGs encode growth-regulating factors (GRF), auxin response factors (ARF), and other proteins involved in the metabolisms of hormones and carbohydrates, etc. Compared with WT, both the chlorophyll contents and the photosynthesis rate were lower in dmc. The contents of glucose, sucrose, fructose, and maltose were lower in dmc. The contents of auxin (IAA) and zeatin (ZA) were significantly lower, but gibberellin (GA) was significantly higher in the tiller tissues of dmc. This research demonstrated that the DEMs regulating hormone and carbohydrate metabolisms were important causes for dmc to not tiller. A primary miRNA-mRNA regulatory model for dmc tillering was established. The lower photosynthesis rate, insufficient energy, and abnormal hormone metabolisms restrict tillering in dmc.

Quantitative Changes in the Transcription of Phytohormone-Related Genes: Some Transcription Factors Are Major Causes of the Wheat Mutant dmc Not Tillering.

Tiller number is an important agronomic trait for grain yield of wheat (Triticum aestivum L.). A dwarf-monoculm wheat mutant (dmc) was obtained from cultivar Guomai 301 (wild type, WT). Here, we explored the molecular basis for the restrained tiller development of the mutant dmc. Two bulked samples of the mutant dmc (T1, T2 and T3) and WT (T4, T5 and T6) with three biological replicates were comparatively analyzed at the transcriptional level by bulked RNA sequencing (RNA-Seq). In total, 68.8 Gb data and 463 million reads were generated, 80% of which were mapped to the wheat reference genome of Chinese Spring. A total of 4904 differentially expressed genes (DEGs) were identified between the mutant dmc and WT. DEGs and their related major biological functions were characterized based on GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) categories. These results were confirmed by quantitatively analyzing the expression profiles of twelve selected DEGs via real-time qRT-PCR. The down-regulated gene expressions related to phytohormone syntheses of auxin, zeatin, cytokinin and some transcription factor (TF) families of TALE, and WOX might be the major causes of the mutant dmc, not tillering. Our work provides a foundation for subsequent tiller development research in the future.

Robust processing of phase dislocations based on combined unwrapping and inpainting approaches.

This Letter proposes a robust processing of phase dislocations to recover continuous phase maps. The approach is based on combined unwrapping and inpainting methods. Phase dislocations are determined using an estimator based on the second order phase gradient. The algorithm is validated using a realistic simulation of phase dislocations, and the phase restoration exhibits only weak errors. A comparison with other inpainting algorithms is also provided, demonstrating the suitability of the approach. The approach is applied to experimental data from off-axis digital holographic interferometry. The phase dislocation from phase data from a wake flow at Mach 0.73 are identified and processed. Excellent phase restoration can be appreciated.

Phase calibration unwrapping algorithm for phase data corrupted by strong decorrelation speckle noise.

Robust phase unwrapping in the presence of high noise remains an open issue. Especially, when both noise and fringe densities are high, pre-filtering may lead to phase dislocations and smoothing that complicate even more unwrapping. In this paper an approach to deal with high noise and to unwrap successfully phase data is proposed. Taking into account influence of noise in wrapped data, a calibration method of the 1st order spatial phase derivative is proposed and an iterative approach is presented. We demonstrate that the proposed method is able to process holographic phase data corrupted by non-Gaussian speckle decorrelation noise. The algorithm is validated by realistic numerical simulations in which the fringe density and noise standard deviation is progressively increased. Comparison with other established algorithms shows that the proposed algorithm exhibits better accuracy and shorter computation time, whereas others may fail to unwrap. The proposed algorithm is applied to phase data from digital holographic metrology and the unwrapped results demonstrate its practical effectiveness. The realistic simulations and experiments demonstrate that the proposed unwrapping algorithm is robust and fast in the presence of strong speckle decorrelation noise.

Modeled microgravity suppressed invasion and migration of human glioblastoma U87 cells through downregulating store-operated calcium entry.

Glioblastoma is the most common brain tumor and is characterized with robust invasion and migration potential resulting in poor prognosis. Previous investigations have demonstrated that modeled microgravity (MMG) could decline the cell proliferation and attenuate the metastasis potential in several cell lines. In this study, we studied the effects of MMG on the invasion and migration potentials of glioblastoma in human glioblastoma U87 cells. We found that MMG stimulation significantly attenuated the invasion and migration potentials, decreased thapsigargin (TG) induced store-operated calcium entry (SOCE) and downregulated the expression of Orai1 in U87 cells. Inhibition of SOCE by 2-APB or stromal interaction molecule 1 (STIM1) downregulation both mimicked the effects of MMG on the invasion and migration potentials in U87 cells. Furthermore, upregulation of Orai1 significantly weakened the effects of MMG on the invasion and migration potentials in U87 cells. Therefore, these findings indicated that MMG stimulation inhibited the invasion and migration potentials of U87 cells by downregulating the expression of Orai1 and sequentially decreasing the SOCE, suggesting that MMG might be a new potential therapeutic strategy in glioblastoma treatment in the future.

Holographic three-dimensional display and hologram calculation based on liquid crystal on silicon device [invited].

Based on scalar diffraction theory and the geometric structure of liquid crystal on silicon (LCoS), we study the impulse responses and image depth of focus in a holographic three-dimensional (3D) display system. Theoretical expressions of the impulse response and the depth of focus of reconstructed 3D images are obtained, and experimental verifications of the imaging properties are performed. The results indicated that the images formed by holographic display based on the LCoS device were periodic image fields surrounding optical axes. The widths of the image fields were directly proportional to the wavelength and diffraction distance, and inversely proportional to the pixel size of the LCoS device. Based on the features of holographic 3D imaging and focal depth, we enhance currently popular hologram calculation methods of 3D objects to improve the computing speed of hologram calculation.

Fine mapping of leaf delayed virescence gene dv4 in Triticum aestivum.

Wheat (Triticum aestivum L.) is one of the most important crops worldwide, and its yield affects national food security. Wheat leaves are key photosynthetic organs where carbohydrates are synthesized for grain yield. Leaf colour mutants are ideal germplasm resources for molecular genetic studies of wheat chloroplast development, chlorophyll synthesis and photosynthesis. We obtained a wheat mutant delayed virescence 4 (dv4) from cultivar Guomai 301. The leaves of mutant dv4 were pale yellow at the seedling stage, golden yellow at the turning green stage, and they started to turn green at the jointing stage. Genetic analysis demonstrated that the yellow-leaf phenotype was controlled by a single recessive gene named as dv4. Gene dv4 was fine mapped in a 1.46 Mb region on chromosome 7DS by SSR and dCAPS marker assays. Three putative candidate genes were identified in this region. Because no leaf colour genes have been reported on wheat chromosome arm 7DS previously, dv4 is a novel leaf colour gene. The result facilitates map-based cloning of dv4 and provides information for the construction of a high-photosynthetic efficiency ideotype for improving wheat yield.

Notch signaling regulates CXCR4 expression and the migration of mesenchymal stem cells.

Mesenchymal stem cells (MSCs) have been used to repair injured tissues through immune-suppression and/or cell replace mechanisms. However, a significant barrier to MSC therapy is insufficient MSC engraftment in injured tissues after systemic administration. Here, we report that cell surface, total protein, and mRNA levels of CXCR4 were significantly increased in MSCs when Notch signaling was interrupted by γ-secretase inhibitor (GSI) or knockout of the transcription factor RBP-J, which mediates signaling from all four mammalian Notch receptors. The GSI-treated or RBP-J deficient MSCs showed stronger migration toward stromal cell-derived factor-1α (SDF-1α) than that of the control. In a mouse hepatic ischemia/reperfusion model, RBP-J deficient MSCs migrated into the injured liver tissues at a significantly higher efficiency than that of the control MSCs. Mice transfused with RBP-J deficient MSCs showed reduced liver damage. Therefore, Notch signaling regulates MSC migration and function, at least partially via the modulation of CXCR4 expression.

Molecular Evolution and Genetic Variation of G2-Like Transcription Factor Genes in Wheat (Triticum aestivum L.).

The GOLDEN2-LIKE (G2-like) gene family members provide significant contributions to the growth and development of plants. In this study, a total of 76 wheat G2-like gene family members (TaG1-TaG76) were detected in the wheat genome and were categorized into three groups (including six subgroups) based on the gene structure and protein motif analyses. These genes were unevenly distributed in 19 of 21 wheat chromosomes. A total of 63 segmental duplication pairs of TaG2-like genes were identified in the wheat genome. The expression levels of all the TaG2-like genes indicated that TaG2-like genes showed different expression patterns in various organs and tissues. Moreover, the transcriptions of TaG2-like genes were significantly affected under abiotic stress (cold, ABA, NaCl, and PEG). This study offered valuable insights into the functional characterization of TaG2-like genes in wheat.

Exogenous strigolactones alleviate drought stress in wheat (Triticum aestivum L.) by promoting cell wall biogenesis to optimize root architecture.

Exogenous strigolactones (SLs, GR24) are widely used to alleviate drought stress in wheat. The physiological and biochemical mechanisms via which SLs help overcome drought stress in wheat shoots have been reported; however, the mechanisms in wheat roots are unclear. The present study explored the effects of the exogenous application of SLs on wheat roots' growth and molecular responses under drought stress using physiological analysis and RNA-seq. RNA-seq of roots showed that SLs mainly upregulated signal transduction genes (SIS8, CBL3, GLR2.8, LRK10L-2.4, CRK29, and CRK8) and transcription factors genes (ABR1, BHLH61, and MYB93). Besides, SLs upregulated a few downstream target genes, including antioxidant genes (PER2, GSTF1, and GSTU6), cell wall biogenesis genes (SUS4, ADF3, UGT13248, UGT85A24, UGT709G2, BGLU31, and LAC5), an aquaporin-encoding gene (TIP4-3), and dehydrin-encoding genes (DHN2, DHN3, and DHN4). As a result, SLs reduced oxidative damage, optimized root architecture, improved leaf-water relation, and alleviated drought damage. Thus, the present study provides novel insights into GR24-mediated drought stress management and a scientific basis for proposing GR24 application.

Executive functions in non-suicidal self-injury comorbid first-episode and drug-naïve depression among adolescents.

Executive functions(EFs) may be associated with the emergence of non-suicidal self-injury(NSSI) due to their role as behavior controllers. EFs includes three core cognitive processes: inhibitory control, working memory, and cognitive flexibility(i.e. the ability to selectively alter cognitive strategies to generate appropriate behavior in the changing environment). This study aimed to systematically explore the three core EFs in depressed adolescents with NSSI. The data was obtained from the baseline data of the Chinese adolescent depression Cohort. The adolescents underwent cognitive assessments to yield domain-specific scores in EFs using the Digit Span Backward test(DSB), the Stroop Color-word interference test- color-word condition(Stroop-CW), and the Wisconsin Card Sorting tests(WCST). The significant differences in WCST scores were found between the NSSI group and the non-NSSI group. NSSI frequency was moderately positively correlated with total errors and negatively correlated with the number of categories completed. The number of categories completed in the "≥200″ NSSI frequency group was significantly lower than that in the "≤10″ NSSI group. The current findings suggested that depressed adolescents who had engaged in NSSI have poorer cognitive flexibility performance compared to adolescents without NSSI. As the frequency of NSSI increased, cognitive flexibility might become worse. These results provide evidence of a connection between executive dysfunctions and NSSI in depressed adolescents.

The wheat leaf delayed virescence of mutant dv4 is associated with the abnormal photosynthetic and antioxidant systems.

Chlorophyll (Chl) is a key pigment for wheat (Triticum aestivum L.) photosynthesis, consequently impacts grain yield. A wheat mutant named as delayed virescence 4 (dv4) was obtained from cultivar Guomai 301 (wild type, WT) treated with ethyl methane sulfonate (EMS). The seedling leaves of dv4 were shallow yellow, apparently were chlorophyll deficient. They started to turn green at the jointing stage and returned to almost ordinary green at the heading stage. Leaf transcriptome comparison of Guomai 301 and dv4 at the jointing stage showed that most differentially expressed genes (DEGs) of transcription and translation were highly expressed in dv4, one key gene nicotianamine aminotransferase A (NAAT-A) involved in the synthesis and metabolism pathways of tyrosine, methionine and phenylalanine was significantly lowly expressed. The expression levels of the most photosynthesis related genes, such as photosystem I (PS I), ATPase and light-harvesting chlorophyll protein complex-related homeotypic genes, and protochlorophyllide reductase A (PORA) were lower; but macromolecule degradation and hypersensitivity response (HR) related gene heat shock protein 82 (HSP82) was highly expressed. Compared to WT, the contents of macromolecules such as proteins and sugars were reduced; the contents of Chl a, Chl b, total Chl, and carotenoids in leaves of dv4 were significantly less at the jointing stage, while the ratio of Chl a / Chl b was the same as that of WT. The net photosynthetic rate, stomatal conductance and transpiration rate of dv4 were significantly lower. The H2O2 content were higher, while the contents of total phenol and malondialdehyde (MDA), antioxidant enzyme activities were lower in leaves of dv4. In conclusion, the reduced contents of macromolecules and photosynthetic pigments, the abnormal photosynthetic and antioxidant systems were closely related to the phenotype of dv4.

Differences in Non-suicidal Self-injury Behaviors between Unipolar Depression and Bipolar Depression in Adolescent Outpatients.

OBJECTIVE: Non-suicidal self-injury (NSSI) has a higher prevalence in adolescents with depressive disorders than in community adolescents. This study examined the differences in NSSI behaviors between adolescents with unipolar depression (UD) and those with bipolar depression (BD). METHODS: Adolescents with UD or BD were recruited from 20 general or psychiatric hospitals across China. The methods, frequency, and function of NSSI were assessed by Functional Assessment of Self-Mutilation. The Beck Suicide Ideation Scale was used to evaluate adolescents' suicidal ideation, and the 10-item Kessler Psychological Distress Scale to estimate the anxiety and depression symptoms. RESULTS: The UD group had higher levels of depression (19.16 vs.17.37, F=15.23, P<0.001) and anxiety symptoms (17.73 vs.16.70, F=5.00, P=0.026) than the BD group. Adolescents with BD had a longer course of NSSI than those with UD (2.00 vs.1.00 year, Z=-3.39, P=0.001). There were no statistical differences in the frequency and the number of methods of NSSI between the UD and BD groups. Depression (r=0.408, P<0.01) and anxiety (r=0.391, P<0.01) were significantly and positively related to NSSI frequency. CONCLUSION: Adolescents with BD had a longer course of NSSI than those with UD. More importantly, NSSI frequency were positively and strongly correlated with depression and anxiety symptoms, indicating the importance of adequate treatment of depression and anxiety in preventing and intervening adolescents' NSSI behaviors.

Wheat gibberellin oxidase genes and their functions in regulating tillering.

Multiple genetic factors control tillering, a key agronomy trait for wheat (Triticum aestivum L.) yield. Previously, we reported a dwarf-monoculm mutant (dmc) derived from wheat cultivar Guomai 301, and found that the contents of gibberellic acid 3 (GA3) in the tiller primordia of dmc were significantly higher. Transcriptome analysis indicated that some wheat gibberellin oxidase (TaGAox) genes TaGA20ox-A2, TaGA20ox-B2, TaGA3ox-A2, TaGA20ox-A4, TaGA2ox-A10 and TaGA2ox-B10 were differentially expressed in dmc. Therefore, this study systematically analyzed the roles of gibberellin oxidase genes during wheat tillering. A total of 63 TaGAox genes were identified by whole genome analysis. The TaGAoxs were clustered to four subfamilies, GA20oxs, GA2oxs, GA3oxs and GA7oxs, including seven subgroups based on their protein structures. The promoter regions of TaGAox genes contain a large number of cis-acting elements closely related to hormone, plant growth and development, light, and abiotic stress responses. Segmental duplication events played a major role in TaGAoxs expansion. Compared to Arabidopsis, the gene collinearity degrees of the GAoxs were significantly higher among wheat, rice and maize. TaGAox genes showed tissue-specific expression patterns. The expressions of TaGAox genes (TaGA20ox-B2, TaGA7ox-A1, TaGA2ox10 and TaGA3ox-A2) were significantly affected by exogenous GA3 applications, which also significantly promoted tillering of Guomai 301, but didn't promote dmc. TaGA7ox-A1 overexpression transgenic wheat lines were obtained by Agrobacterium mediated transformation. Genomic PCR and first-generation sequencing demonstrated that the gene was integrated into the wheat genome. Association analysis of TaGA7ox-A1 expression level and tiller number per plant demonstrated that the tillering capacities of some TaGA7ox-A1 transgenic lines were increased. These data demonstrated that some TaGAoxs as well as GA signaling were involved in regulating wheat tillering, but the GA signaling pathway was disturbed in dmc. This study provided valuable clues for functional characterization of GAox genes in wheat.

Relationship between perceived stress and depression in Chinese front-line medical staff during COVID-19: A conditional process model.

BACKGROUND: Sustained stress during COVID-19 may be associated with depression in front-line medical staff, which would expose them to severe threats. This study aimed to examine whether the relationship between perceived stress and depression is mediated by insomnia, and whether this mediation is moderated by resilience. METHODS: For front-line medical staff, this study used online questionnaire to evaluate their perceived stress, depression, insomnia and resilience. A conditional process model was performed to examine the relationship between perceived stress and depression, as well as the mediating effect of insomnia and the moderating effect of resilience. RESULTS: A total of 606 front-line medical staff completed the survey. Higher level of perceived stress was significantly positively related to severe insomnia and depression. In addition, insomnia was positively related to depression, while resilience could moderate the effect of perceived stress on depression by direct and indirect paths. LIMITATIONS: The causality among perceived stress, depression, insomnia and resilience is difficult to be verified. CONCLUSIONS: Perceived stress is positively related to depression, and insomnia can mediate the effect of perceived stress on depression. In addition, the effect of perceived stress on depression, whether direct or indirect, is moderated by resilience, which is a protective factor for mental health.