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1.
New Phytol ; 2024 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-39301581

RESUMO

Redistribution of precipitation across seasons is a widespread phenomenon affecting dryland ecosystems globally. However, the impacts of shifting seasonal precipitation patterns on carbon (C) cycling and sequestration in dryland ecosystems remain poorly understood. In this study, we conducted a 10-yr (2013-2022) field manipulative experiment that altered the timing of growing-season precipitation peaks in a semi-arid grassland. We found that the delayed precipitation peak suppressed plant growth and thus reduced gross ecosystem productivity, ecosystem respiration, and net ecosystem productivity due to middle growing-season water stress. Surprisingly, shifting more precipitation to the early growing season can advance plant development, increase the dominance of drought-tolerant forbs, and thus compensate for the negative impacts of middle growing-season water stress on ecosystem C cycling, leading to a neutral change in grassland C sink. Our findings indicate that greater precipitation and plant development in spring could act as a crucial mechanism, maintaining plant growth and stabilizing ecosystem C sink. This underscores the urgent need to incorporate precipitation seasonality into Earth system models, which is crucial for improving projections of terrestrial C cycling and sequestration under future climate change scenarios.

2.
Sci Total Environ ; 924: 171573, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38462005

RESUMO

The critical impacts of microclimate on carbon (C) cycling have been widely reported. However, the potential effects of global change on wetland microclimate remain unclear, primarily because of the absence of field manipulative experiment in inundated wetland. This study was designed to examine the effects of nighttime warming and nitrogen (N) addition on air, water, and sediment temperature and also reveal the controlling factors in a Phragmites australis dominated freshwater wetland on the North China Plain. Nighttime warming increased daily air, water, and sediment temperature by 0.24 °C, 0.27 °C, and 0.36 °C, respectively. The diurnal temperature range of water was decreased by 0.44 °C under nighttime warming, whereas warming had no effect on diurnal temperature range of air and sediment. In addition, N addition caused a reduction of 0.20 °C and 0.14 °C in daily water and sediment temperature by increasing vegetation coverage. There was a significant interaction between nighttime warming and N addition on water temperature. Furthermore, the vapor pressure deficit is the main factor affecting the extent of the warming-induced increases in air temperature. The changes of height and leaf area index of Phragmites australis are responsible for the cooling effects in the N addition plots. This study provides empirical evidence for the positive climate warming - microclimate feedback in freshwater wetland. However, N deposition leads to decreased water and sediment temperature. Our findings highlight the importance of incorporating the differential impacts of nighttime warming and N addition on air, water, and sediment temperature into the predictions of wetland C cycling responses to climate change.

3.
Biology (Basel) ; 12(5)2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37237512

RESUMO

Climate warming has profoundly influenced community structure and ecosystem functions in the terrestrial biosphere. However, how asymmetric rising temperatures between daytime and nighttime affect soil microbial communities that predominantly regulate soil carbon (C) release remains unclear. As part of a decade-long warming manipulation experiment in a semi-arid grassland, we aimed to examine the effects of short- and long-term asymmetrically diurnal warming on soil microbial composition. Neither daytime nor nighttime warming affected soil microbial composition in the short term, whereas long-term daytime warming instead of nighttime warming decreased fungal abundance by 6.28% (p < 0.05) and the ratio of fungi to bacteria by 6.76% (p < 0.01), which could be caused by the elevated soil temperature, reduced soil moisture, and increased grass cover. In addition, soil respiration enhanced with the decreasing fungi-to-bacteria ratio, but was not correlated with microbial biomass C during the 10 years, indicating that microbial composition may be more important than biomass in modulating soil respiration. These observations highlight the crucial role of soil microbial composition in regulating grassland C release under long-term climate warming, which facilitates an accurate assessment of climate-C feedback in the terrestrial biosphere.

4.
Dela J Public Health ; 8(3): 14-19, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36177168

RESUMO

Objectives: To understand how place and social position shape experiences of HIV stigma among people living with HIV (PLWH) in Delaware. HIV stigma impedes the health and wellbeing of PLWH. Yet, HIV stigma is often studied through psychosocial perspectives without considering social-structural conditions. Recent theorists have hypothesized that place and social position, two key social-structural conditions, fundamentally shape PLWH's experiences of stigma. Due to residential segregation of racial/ethnic and lesbian, gay, bisexual, transgender, and queer (LGBTQ) populations, place and social position are often inextricably intertwined within the U.S. Methods: Qualitative interviews were conducted with 42 PLWH and 14 care providers in 2017. Interviews were conducted with English- and Spanish-speaking PLWH in all three counties in Delaware, including: Wilmington in New Castle County, Smyrna in Kent County, and Georgetown in Sussex County. Results: Results suggest that PLWH's experiences of HIV stigma are shaped by place and social position. Although HIV stigma is still prevalent across Delaware, participants reported that HIV stigma is more pronounced in Kent and Sussex counties and in rural areas. Latinx and Haitian PLWH are at greater risk of experiencing HIV stigma than other racial/ethnic groups, with participants identifying misinformation within Latinx and Haitian communities as a key driver of HIV stigma. HIV stigma is further compounded by medical mistrust in the Haitian community. In contrast, participants noted that LGBTQ PLWH in Sussex County are somewhat buffered from HIV stigma by the LGBTQ community, which is reported to be more knowledgeable about HIV and accepting of PLWH. Conclusions: Multi-level interventions that address social-structural conditions in addition to individual-level factors are recommended to best address HIV stigma in Delaware. Interventions should target drivers of stigma, such as lack of knowledge, and consider how place and social position uniquely shape PLWH's experiences of stigma.

5.
J Immunol Res ; 2018: 4564328, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29651441

RESUMO

BACKGROUND: In our previous study, mouse double minute 2 homolog (MDM2), insulin-like growth factor 1 (IGF1), signal transducer and activator of transcription 1 (STAT1), and Rac family small GTPase 1 (RAC1) were correlated with the recurrence of giant cell tumor of bone (GCT). The aim of this study is to use a large cohort study to confirm the involvement of these four genes in GCT recurrence. METHODS: The expression of these four genes was detected and compared between GCT patients with or without recurrence. The correlation between the expression of these four genes and clinical characteristics was evaluated. Protein-protein interaction (PPI) network was constructed for functional enrichment analysis. RESULTS: It showed that the expression levels of MDM2, IGF1, STAT1, and RAC1 in GCT patients with recurrence were significantly higher than those in GCT patients without recurrence (P < 0.05). Multivariate logistic regression analysis suggested that several clinical characteristics may influence prognosis. A PPI network was constructed using the four genes as hub genes. Functional enrichment analysis showed that this network involves many important biological progress mediated by these four genes, including immune response. CONCLUSION: MDM2, IGF1, STAT1, and RAC1 are associated with GCT recurrence, which might serve as biomarkers for GCT recurrence.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias Ósseas/patologia , Tumor de Células Gigantes do Osso/patologia , Fator de Crescimento Insulin-Like I/metabolismo , Recidiva Local de Neoplasia/genética , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Fator de Transcrição STAT1/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Adolescente , Adulto , Idoso , Biomarcadores Tumorais/genética , Neoplasias Ósseas/diagnóstico , Neoplasias Ósseas/metabolismo , Estudos de Coortes , Feminino , Tumor de Células Gigantes do Osso/diagnóstico , Tumor de Células Gigantes do Osso/metabolismo , Humanos , Imuno-Histoquímica , Fator de Crescimento Insulin-Like I/genética , Masculino , Pessoa de Meia-Idade , Prognóstico , Mapas de Interação de Proteínas , Proteínas Proto-Oncogênicas c-mdm2/genética , Fator de Transcrição STAT1/genética , Adulto Jovem , Proteínas rac1 de Ligação ao GTP/genética
6.
Artigo em Chinês | MEDLINE | ID: mdl-17639696

RESUMO

OBJECTIVE: To investigate the morphological characteristics of the adult worms of Taenia saginata from four areas of Western China. METHODS: 42, 41, 7 and 18 integral worms of Taenia saginata were collected from Duyun and Congjiang of Guizhou Province, Wushi of Xinjiang, and Lhasa of Tibet respectively. The length of worms was measured and the segments were counted. The specimens of scolex, mature and gravid proglottids of the worms were stained, measured and photographed. RESULTS: The mean length of the worms from Duyun, Congjiang, Wushi and Lasa was (1.81+/-0.69) m, (3.84+/-1.32) m, (2.76+/-0.86) m and (3.72+/-1.12) m, and with (574.64+/-189.33), (913.84+/-317.41), (971.29+/-168.30) and (940.38+/-368.26) proglottids, respectively. The mean ratio of the distance between two lateral excretory vessels and the length of vitellarium of the mature proglottids was (1.71+/-0.13), (2.23+/-0.06), (2.03+/-0.21), (2.31+/-0.15) respectively. All the 3 parameters of the worms from Duyun were significantly less than those from other 3 areas (P<0.05). Rudimentary rostellum was found obviously in 3 of 10 scolices of the worms from Duyun. CONCLUSION: The morphological characteristics of the adult worms from Duyun are similar to that of Taenia saginata asiatica, while those of the worms from Congjiang, Wushi and Lhasa are alike to those of Taenia saginata saginata.


Assuntos
Cisticercose/parasitologia , Taenia saginata/anatomia & histologia , Teníase/parasitologia , Animais , China , Humanos , Contagem de Ovos de Parasitas , Taenia saginata/isolamento & purificação
7.
Artigo em Chinês | MEDLINE | ID: mdl-15108532

RESUMO

OBJECTIVE: To study epidemiological factors of taeniasis and to detect amino acid and element components of adult worms in Duyun of Guizhou Province. METHODS: 1. Traditional methods were used for epidemiological investigation. 2. Automatic amino acid analyzer and bioassay were applied for the detection. RESULTS: Among 70 persons with clinical symptoms, 25 patients (24 men and 1 woman) were found to have adult taenia worms in their faeces after taking Areca catechu L. and other drugs. Sixteen amino acids and 12 elements were determined in adult worms. CONCLUSION: Duyun area in Guizhou is a highly endemic area of taeniasis. The pathogenic parasite is identified as Taenia saginata asiatica. Its clinical symptoms are similar to that of Taenia saginata saginata.


Assuntos
Taenia/química , Teníase/epidemiologia , Adulto , Aminoácidos/análise , Animais , China/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Taenia/classificação , Teníase/parasitologia , Oligoelementos/análise
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