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1.
Proc Natl Acad Sci U S A ; 118(15)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33827929

RESUMO

We previously determined that several diets used to rear Aedes aegypti and other mosquito species support the development of larvae with a gut microbiota but do not support the development of axenic larvae. In contrast, axenic larvae have been shown to develop when fed other diets. To understand the mechanisms underlying this dichotomy, we developed a defined diet that could be manipulated in concert with microbiota composition and environmental conditions. Initial studies showed that axenic larvae could not grow under standard rearing conditions (27 °C, 16-h light: 8-h dark photoperiod) when fed a defined diet but could develop when maintained in darkness. Downstream assays identified riboflavin decay to lumichrome as the key factor that prevented axenic larvae from growing under standard conditions, while gut community members like Escherichia coli rescued development by being able to synthesize riboflavin. Earlier results showed that conventional and gnotobiotic but not axenic larvae exhibit midgut hypoxia under standard rearing conditions, which correlated with activation of several pathways with essential growth functions. In this study, axenic larvae in darkness also exhibited midgut hypoxia and activation of growth signaling but rapidly shifted to midgut normoxia and arrested growth in light, which indicated that gut hypoxia was not due to aerobic respiration by the gut microbiota but did depend on riboflavin that only resident microbes could provide under standard conditions. Overall, our results identify riboflavin provisioning as an essential function for the gut microbiota under most conditions A. aegypti larvae experience in the laboratory and field.


Assuntos
Aedes/crescimento & desenvolvimento , Microbioma Gastrointestinal , Riboflavina/biossíntese , Aedes/microbiologia , Animais , Escherichia coli/metabolismo , Escherichia coli/patogenicidade
2.
Clin Radiol ; 77(8): 613-620, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35589431

RESUMO

AIM: To investigate if the pattern of fluorine-18-labelled sodium fluoride (18F-NaF) uptake on integrated positron-emission tomography (PET)/magnetic resonance imaging (MRI) of bone marrow lesions (BML) and osteophytes differs between different knee compartments. MATERIALS AND METHODS: Sixteen patients with no prior history of knee injury with or without pain were recruited for the study. The images of both knees were acquired on simultaneous PET/MRI. The acquisition was done after 45 minutes of intravenous injection of 18F-NaF 185-370 MBq (5-10 mCi) for 40 minutes. Each knee was divided into eight compartments patella, trochlea, medial central femur, lateral central femur, medial posterior femur, lateral posterior femur, medial tibia, lateral tibia, and cruciate ligament insertion specifically for BML. BML and osteophytes were scored using MRI Osteoarthritis Knee Score (MOAKS) criteria and their corresponding maximum standardised uptake values (SUVmax) recorded. RESULTS: BML and osteophytes both showed statistically significant differences among knee compartments, i.e., p-value <0.000 and < 0.043 respectively. SUVmax for BML and osteophytes was greatest in the medial tibia. CONCLUSION: 18F-NaF PET/MRI showed that BML and osteophytes had differential uptake values due to bone remodelling amongst the various knee compartments and this may help to design disease-modifying osteoarthritis drugs in the future.


Assuntos
Doenças Ósseas , Osteoartrite do Joelho , Osteófito , Humanos , Articulação do Joelho/diagnóstico por imagem , Articulação do Joelho/patologia , Imageamento por Ressonância Magnética/métodos , Osteoartrite do Joelho/diagnóstico por imagem , Osteófito/patologia , Tomografia por Emissão de Pósitrons/métodos , Fluoreto de Sódio
3.
Ann Bot ; 125(2): 365-376, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31532484

RESUMO

BACKGROUND AND AIMS: Coastal wetlands have evolved to withstand stressful abiotic conditions through the maintenance of hydrologic feedbacks between vegetation production and flooding. However, disruption of these feedbacks can lead to ecosystem collapse, or a regime shift from vegetated wetland to open water. To prevent the loss of critical coastal wetland habitat, we must improve understanding of the abiotic-biotic linkages among flooding and wetland stability. The aim of this research was to identify characteristic landscape patterns and thresholds of wetland degradation that can be used to identify areas of vulnerability, reduce flooding threats and improve habitat quality. METHODS: We measured local- and landscape-scale responses of coastal wetland vegetation to flooding stress in healthy and degrading coastal wetlands. We hypothesized that conversion of Spartina patens wetlands to open water could be defined by a distinct change in landscape configuration pattern, and that this change would occur at a discrete elevation threshold. KEY RESULTS: Despite similarities in total land and water cover, we observed differences in the landscape configuration of vegetated and open water pixels in healthy and degrading wetlands. Healthy wetlands were more aggregated, and degrading wetlands were more fragmented. Generally, greater aggregation was associated with higher wetland elevation and better drainage, compared with fragmented wetlands, which had lower elevation and poor drainage. The relationship between vegetation cover and elevation was non-linear, and the conversion from vegetated wetland to open water occurred beyond an elevation threshold of hydrologic stress. CONCLUSIONS: The elevation threshold defined a transition zone where healthy, aggregated, wetland converted to a degrading, fragmented, wetland beyond an elevation threshold of 0.09 m [1988 North American Vertical Datum (NAVD88)] [0.27 m mean sea level (MSL)], and complete conversion to open water occurred beyond 0.03 m NAVD88 (0.21 m MSL). This work illustrates that changes in landscape configuration can be used as an indicator of wetland loss. Furthermore, in conjunction with specific elevation thresholds, these data can inform restoration and conservation planning to maximize wetland stability in anticipation of flooding threats.


Assuntos
Ecossistema , Áreas Alagadas , Conservação dos Recursos Naturais , Poaceae
4.
J Sep Sci ; 43(7): 1256-1264, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32012437

RESUMO

Process streams of agro-food industries are often large and viscous. In order to fractionate such a stream the viscosity can be reduced by either a high temperature or dilution, the former is not an option in case of temperature sensitive components. Such streams are diluted prior to chromatographic fractionation, resulting in even larger volumes and high energy costs for sub-sequential water removal. The influence of feed viscosity on the performance of simulated moving bed chromatography has been investigated in a case study of the recovery of a γ-aminobutyric acid rich fraction from tomato serum. This work addresses the chromatographic system design, evaluates results from a pilot scale operation, and uses these to calculate the productivity and water use at elevated feed concentration. At the two higher feed viscosities (2.5 and 4 mPa·s) water use is lower and productivity higher, compared to the lowest feed viscosity (1 mPa·s). The behavior of the sugars for different feed viscosities can be described well by the model using the ratio of feed to eluent as dilution factor. The behavior of γ-aminobutyric acid is highly concentration dependent and the recovery could not be accurately predicted.


Assuntos
Solanum lycopersicum/química , Ácido gama-Aminobutírico/isolamento & purificação , Viscosidade , Ácido gama-Aminobutírico/química
5.
Phys Chem Chem Phys ; 21(28): 15854-15860, 2019 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-31282515

RESUMO

Multiferroic Y-doped BiFeO3 (BY10FO) thin films were deposited on FTO coated glass substrate using sol-gel spin coating technique. Y-doping causes structural distortion without changing the structure of the parent BiFeO3 (rhombohedral: R3c). The M-H hysteresis curve reveals that the BY10FO film exhibits saturation magnetization at a low-coercive field by suppressing the spiral spin modulated structure. The bipolar resistive switching behavior has been investigated on a Ag/BY10FO/FTO hetero-structure through conventional I-V curve measurements and the device can produce an ON/OFF ratio of around 12 over 30 complete testing cycles. The space charge limited current and Schottky barrier emission conduction mechanism play a crucial role in switching the states between HRS and LRS. The impedance spectroscopy analysis at HRS and LRS confirms the significant degradation of resistance from MΩ to kΩ. The switching mechanism in the hetero-structure is due to migration and recombination of oxygen vacancies present in the film. The non-degradation of the Ag/BY10FO/FTO device after several testing cycles confirms that the switching of resistance between ON and OFF states is reproducible, reversible and controllable to be used for possible future non-volatile resistive random access memory application.

6.
Compr Psychiatry ; 73: 97-104, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27930952

RESUMO

INTRODUCTION: Food addiction is a controversial concept. The potential influence of food addiction on patients' psychosocial functioning and well-being has not been well established. The purpose of this study was to examine the relationships between psychosocial functioning (depressive symptoms and health-related quality of life [HRQOL]) and food addiction as measured by the Yale Food Addiction Scale (YFAS). We also explored whether food addiction contributed additional variance in explaining psychosocial functioning, beyond demographic and clinical factors (e.g., binge eating). METHODS: The sample included 178 participants (mean age=44.2±11.2years; BMI=40.9±5.9kg/m2; 88.2% female; 70.8% Black) with obesity seeking treatment for weight loss. Participants completed the Medical Outcomes Study 36-Item Short-Form Health Survey, Impact of Weight on Quality of Life-Lite, Patient Health Questionnaire, YFAS, and Questionnaire on Eating and Weight Patterns-5. RESULTS: Twelve (6.7%) participants met criteria for food addiction, with 4 (33.3%) of these participants having co-occurring binge eating disorder. After adjusting for covariates, the number of food addiction symptoms accounted for 6.5% to 16.3% of additional variance in general HRQOL, 5.0% to 21.5% in weight-related HRQOL, and 19.1% in symptoms of depression. CONCLUSIONS: In this treatment-seeking sample of participants, we found a low prevalence of food addiction, suggesting that addictive-like eating is unlikely to be a causal mechanism for most people with obesity. However, individuals who met criteria for food addiction had reduced psychosocial functioning compared to those who did not meet criteria. Individuals with addictive-like eating may require additional psychosocial support.


Assuntos
Comportamento Aditivo/psicologia , Transtorno da Compulsão Alimentar/psicologia , Comportamento Alimentar/psicologia , Obesidade/psicologia , Adulto , Comportamento Aditivo/complicações , Comportamento Aditivo/epidemiologia , Transtorno da Compulsão Alimentar/complicações , Transtorno da Compulsão Alimentar/epidemiologia , Peso Corporal , Estudos Transversais , Depressão/complicações , Depressão/epidemiologia , Depressão/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pennsylvania/epidemiologia , Prevalência , Qualidade de Vida
8.
Appetite ; 105: 60-70, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27208596

RESUMO

The present study examined the effect of a picture-picture evaluative conditioning (EC) procedure on soft drink (soda) outcomes, including negative implicit attitudes, consumption during a taste test, and real-world consumption reported during the week after the intervention. In the EC condition (n = 43), soda images were paired with disgust images and water images were paired with pleasant images, whereas in the control condition (n = 41), the same images were viewed without pairing. The EC condition showed a larger reduction in real-world soda consumption across the week following the intervention. However, individuals in the EC condition did not consume less soda during a taste test immediately following the intervention. EC only significantly increased negative implicit attitudes towards soda among individuals who already had relatively higher baseline negative attitudes. These findings generally favored the potential for EC to impact soda drinking habits, but suggest that a brief EC intervention may not be strong enough to change attitudes towards a well-known brand unless negative attitudes are already present.


Assuntos
Bebidas Gaseificadas/efeitos adversos , Condicionamento Psicológico , Dieta Saudável , Conhecimentos, Atitudes e Prática em Saúde , Modelos Psicológicos , Obesidade/prevenção & controle , Cooperação do Paciente , Adolescente , Fenômenos Fisiológicos da Nutrição do Adolescente , Adulto , Comportamento Alimentar , Feminino , Seguimentos , Preferências Alimentares , Hábitos , Humanos , Masculino , Obesidade/etiologia , Philadelphia , Autorrelato , Adulto Jovem
9.
Appetite ; 103: 176-183, 2016 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-27083129

RESUMO

OBJECTIVE: Obesity is largely attributable to excess caloric intake, in particular from "junk" foods, including salty snack foods. Evidence suggests that neurobiological preferences to consume highly hedonic foods translate (via implicit processes) into poor eating choices, unless overturned by inhibitory mechanisms or interrupted by explicit processes. The primary aim of the current study was to test the independent and combinatory effects of a computerized inhibitory control training (ICT) and a mindful decision-making training (MDT) designed to facilitate de-automatization. METHODS: We randomized 119 habitual salty snack food eaters to one of four short, training conditions: MDT, ICT, both MDT and ICT, or neither (i.e., psychoeducation). For 7 days prior to the intervention and 7 days following the intervention, participants reported on their salty snack food consumption 2 times per day, on 3 portions of their days, using a smartphone-based ecological momentary assessment system. Susceptibility to emotional eating cues was measured at baseline. RESULTS: Results indicated that the effect of MDT was consistent across levels of trait emotional eating, whereas the benefit of ICT was apparent only at lower levels of emotional eating. No synergistic effect of MDT and ICT was detected. CONCLUSIONS: These results provide qualified support for the efficacy of both types of training for decreasing hedonically-motivated eating. Moderation effects suggest that those who eat snack foods for reasons unconnected to affective experiences (i.e., lower in emotional eating) may derive benefit from a combination of ICT and MDT. Future research should investigate the additive benefit of de-automization training to standard weight loss interventions.


Assuntos
Preferências Alimentares/psicologia , Atenção Plena/educação , Obesidade/prevenção & controle , Autocontrole/psicologia , Lanches/psicologia , Adolescente , Adulto , Sinais (Psicologia) , Tomada de Decisões , Feminino , Humanos , Inibição Psicológica , Masculino , Pessoa de Meia-Idade , Motivação , Inquéritos e Questionários , Fatores de Tempo
11.
Bull Environ Contam Toxicol ; 95(4): 465-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26253841

RESUMO

There are no known biological requirements for lead (Pb), and elevated Pb levels in birds can cause a variety of sub-lethal effects and mortality. Historic and current levels of Pb in mottled ducks (Anas fulvigula) suggest that environmental sources of Pb remain available on the upper Texas coast. Because of potential risks of Pb exposure among coexisting marsh birds, black-necked stilt (Himantopus mexicanus) blood Pb concentrations were measured during the breeding season. Almost 80 % (n = 120) of 152 sampled stilts exceeded the background threshold (>20 µg/dL) for Pb exposure. However, blood Pb concentrations did not vary by age or gender, and toxic or potentially lethal concentrations were rare (<5 %). Consistent, low-level blood Pb concentrations of black-necked stilts in this study suggest the presence of readily bioavailable sources of Pb, although potential impacts on local stilt populations remain unclear.


Assuntos
Charadriiformes/metabolismo , Patos/metabolismo , Chumbo/sangue , Animais , Cruzamento , Feminino , Masculino , Medição de Risco , Estações do Ano , Texas
12.
Ann Oncol ; 25(11): 2284-2289, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25193993

RESUMO

BACKGROUND: Whether or not toxicity predicts clinical outcomes has long been a question regarding cancer treatments. While prior studies have focused on specific cancers, therapies, and toxicities, no comprehensive evidence exists on whether treatment toxicity predicts favorable outcomes. METHODS: We abstracted treatment toxicity and clinical outcome data from a sample of phase III oncology randomized clinical trials (n = 99 trials). We investigated whether treatments with relatively greater toxicity compared with their controls had relatively higher, lower, or equivocal rates of clinical efficacy, measured by progression-free survival (PFS) and overall survival (OS). Several toxicities were assessed (all grades, grades III/IV, cutaneous rash, gastrointestinal toxicity, and myelosuppression). RESULTS: Toxicity and efficacy were greater among treatments than controls (e.g. 3.5 instances of all-grade toxicity per patient in treatment arms versus 2.8 instances in controls, P < 0.001; mean PFS of 9.1 months across treatment arms versus 7.1 months across controls, P < 0.001; mean OS of 18.6 months across treatment arms versus 16.9 months across controls, P < 0.001). Across trials, greater relative treatment toxicity was strongly associated with greater PFS in treatments versus controls (P < 0.001), but not OS (P = 0.44). Although higher relative rates of myelosuppression and cutaneous rash among treatments were not associated with greater treatment efficacy, greater relative gastrointestinal toxicity among treatments was associated with greater relative PFS compared with controls (P = 0.007). CONCLUSION: Across trials, treatments with relatively greater all-grade toxicity compared with controls are associated with relatively greater PFS but not OS.


Assuntos
Antineoplásicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Intervalo Livre de Doença , Neoplasias/tratamento farmacológico , Antineoplásicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Ensaios Clínicos Fase III como Assunto , Humanos , Neoplasias/patologia , Ensaios Clínicos Controlados Aleatórios como Assunto , Resultado do Tratamento
13.
Int J Oral Maxillofac Surg ; 53(8): 672-676, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38556432

RESUMO

Bizarre parosteal osteochondromatous proliferations (BPOPs) are distinct clinical-pathological entities that demonstrate combinations of atypical-appearing osseous and chondromatous tissues. These lesions are usually reactive in nature. Histopathologically, 'bizarre' cartilage is a characteristic feature of this lesion. BPOPs usually represent slow-growing painless bony hard protuberances that arise from the surface of affected bone cortices, typically the metacarpals, metatarsals, and phalanges. The occurrence of these lesions in the skull and jaws is sporadic. This case report highlights the clinical presentation, histopathological characteristics, and management of BPOP arising from the supraorbital rim in a 61-year-old female patient.


Assuntos
Osteocondroma , Humanos , Feminino , Pessoa de Meia-Idade , Osteocondroma/patologia , Osteocondroma/diagnóstico por imagem , Osteocondroma/cirurgia , Diagnóstico Diferencial , Osso Temporal/patologia , Osso Temporal/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Neoplasias Ósseas/patologia , Neoplasias Ósseas/diagnóstico por imagem , Neoplasias Ósseas/cirurgia , Biópsia
14.
Rev Gastroenterol Mex (Engl Ed) ; 89(1): 25-30, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-36707393

RESUMO

INTRODUCTION AND AIM: Thiopurine-related leukopenia is associated with polymorphisms in the thiopurine methyltransferase (TPMT) and nucleoside diphosphate-linked moiety X type motif 15 (NUDT15) genes. However, those polymorphisms explain only a fraction of thiopurine-related leukopenia. Our aim was to study the role of an inosine triphosphate pyrophosphatase (ITPA) polymorphism in patients with inflammatory bowel disease (IBD) and thiopurine-related leukopenia that was unexplained by the TPMT and NUDT15 polymorphisms. MATERIAL AND METHODS: We enrolled consecutive IBD patients on thiopurines (azathioprine or 6-mercaptopurine) from January 2019-March 2020, at a tertiary care center in North India. The presence of the ITPA (C.94C > A) polymorphism was evaluated in all patients, along with its association with thiopurine-related leukopenia. RESULTS: Of the 33 patients (from a total of 119 patients) that developed leukopenia, 8 had the TPMT (n = 1) or NUDT15 (n = 7) polymorphism. Of the remaining 111 patients, their mean age was 36.36 ±â€¯13.54 years and 57 (51.3%) were males. Twenty-five (21.01%) had unexplained leukopenia. The ITPA polymorphism was detected in 4 (16%) patients in the unexplained leukopenia group and 24 (27.9%) patients in the non-leukopenia group (p = 0.228). The odds ratio for predicting leukopenia with the ITPA polymorphism was 0.4921 (95% CI 0.1520-1.5830, p = 0.234). CONCLUSION: The ITPA (C.94C > A) polymorphism was frequently detected in the study population but was not predictive for leukopenia in patients with IBD on thiopurine therapy.

15.
AJNR Am J Neuroradiol ; 44(3): 236-246, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36657945

RESUMO

PET with amino acid tracers provides additional insight beyond MR imaging into the biology of gliomas that can be used for initial diagnosis, delineation of tumor margins, planning of surgical and radiation therapy, assessment of residual tumor, and evaluation of posttreatment response. Hybrid PET MR imaging allows the simultaneous acquisition of various PET and MR imaging parameters in a single investigation with reduced scanning time and improved anatomic localization. This review aimed to provide neuroradiologists with a concise overview of the various amino acid tracers and a practical understanding of the clinical applications of amino acid PET MR imaging in glioma management. Future perspectives in newer advances, novel radiotracers, radiomics, and cost-effectiveness are also outlined.


Assuntos
Neoplasias Encefálicas , Glioma , Humanos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/terapia , Neoplasias Encefálicas/patologia , Aminoácidos , Glioma/diagnóstico por imagem , Glioma/terapia , Glioma/patologia , Tomografia por Emissão de Pósitrons/métodos , Imageamento por Ressonância Magnética/métodos
16.
Int J Eat Disord ; 45(4): 512-23, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22271593

RESUMO

OBJECTIVE: To determine how often patients diagnosed with bulimia nervosa (BN) surpass their highest pre-morbid weight during the course of their disorder. METHOD: The weight histories of individuals with BN were determined using retrospective weight data (Study 1) and combined retrospective/prospective data (Study 2). RESULTS: Retrospective analyses indicated that 59.0% (n = 46) and 61.8% (n = 110), respectively, reported that their highest weight was reached after developing BN. In Study 2, 35.3% of participants superseded their highest pre-enrollment weights during 8 years of follow-up, and 71.6% reached a post-morbid highest weight before remission. Across studies, the primary difference between patients who did and did not reach their highest weight post-morbidly was that those who did had an earlier age of onset and longer duration of BN. DISCUSSION: Findings are discussed in terms of possible links between BN and weight-gain proneness, weight fluctuation across the course of BN, and implications for treating BN.


Assuntos
Peso Corporal/fisiologia , Bulimia Nervosa/fisiopatologia , Terapia Cognitivo-Comportamental , Adolescente , Adulto , Bulimia Nervosa/psicologia , Bulimia Nervosa/terapia , Feminino , Humanos , Estudos Longitudinais , Estudos Retrospectivos , Resultado do Tratamento
19.
J Stomatol Oral Maxillofac Surg ; 122(3): 319-324, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32911101

RESUMO

Distraction osteogenesis is a popular treatment modality to lengthen the mandible. It is commonly performed in wide varieties of craniofacial syndromes, temporomandibular joint (TMJ) ankylosis, and obstructive sleep apnea cases requiring a significant amount of mandibular lengthening. There are many complications associated with mandibular distraction osteogenesis procedure and the breakage of the distractor is very rare. There are few reports in the literature mentioning the breakage of a distractor. This article highlights an up-to-date knowledge of the etiology and prevention of mandibular distractor breakage and a case report which was managed well after bilateral internal mandibular distractor breakage. This is the first case report describing the spontaneous bilateral mandibular distractor breakage during the active phase of distraction osteogenesis.


Assuntos
Anquilose , Micrognatismo , Osteogênese por Distração , Transtornos da Articulação Temporomandibular , Humanos , Mandíbula/cirurgia , Osteogênese por Distração/efeitos adversos , Transtornos da Articulação Temporomandibular/diagnóstico , Transtornos da Articulação Temporomandibular/etiologia , Transtornos da Articulação Temporomandibular/cirurgia
20.
Plants (Basel) ; 10(9)2021 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-34579374

RESUMO

Climate extremes are becoming more frequent with global climate change and have the potential to cause major ecological regime shifts. Along the northern Gulf of Mexico, a coastal wetland in Texas suffered sudden vegetation dieback following an extreme precipitation and flooding event associated with Hurricane Harvey in 2017. Historical salt marsh dieback events have been linked to climate extremes, such as extreme drought. However, to our knowledge, this is the first example of extreme precipitation and flooding leading to mass mortality of the salt marsh foundation species, Spartina alterniflora. Here, we investigated the relationships between baseline climate conditions, extreme climate conditions, and large-scale plant mortality to provide an indicator of ecosystem vulnerability to extreme precipitation events. We identified plant zonal boundaries along an elevation gradient with plant species tolerant of hypersaline conditions, including succulents and graminoids, at higher elevations, and flood-tolerant species, including S. alterniflora, at lower elevations. We quantified a flooding threshold for wetland collapse under baseline conditions characterized by incremental increases in flooding (i.e., sea level rise). We proposed that the sudden widespread dieback of S. alterniflora following Hurricane Harvey was the result of extreme precipitation and flooding that exceeded this threshold for S. alterniflora survival. Indeed, S. alterniflora dieback occurred at elevations above the wetland collapse threshold, illustrating a heightened vulnerability to flooding that could not be predicted from baseline climate conditions. Moreover, the spatial pattern of vegetation dieback indicated that underlying stressors may have also increased susceptibility to dieback in some S. alterniflora marshes.Collectively, our results highlight a new mechanism of sudden vegetation dieback in S. alterniflora marshes that is triggered by extreme precipitation and flooding. Furthermore, this work emphasizes the importance of considering interactions between multiple abiotic and biotic stressors that can lead to shifts in tolerance thresholds and incorporating climate extremes into climate vulnerability assessments to accurately characterize future climate threats.

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