Testing general relativity with supermassive black holes using X-ray reflection spectroscopy

In this paper, we review our current efforts to test General Relativity in the strong field regime by studying the reflection spectrum of supermassive black holes. So far we have analyzed 11 sources with observations of NuSTAR, Suzaku, Swift, and XMM-Newton. Our results are consistent with general relativity, according to which the spacetime metric around astrophysical black holes should be well approximated by the Kerr solution. We discuss the systematic uncertainties in our model and we present a preliminary study on the impact of some of them on the measurement of the spacetime metric.Comment: 22 pages, 12 figures. Review article prepared for a Special Issue of Universe and based on some talks given at the meeting "Recent Progress in Relativistic Astrophysics" (6-8 May 2019, Shanghai, China

Effect of Ultrasonic Treatment on the Digestion Characteristics of Glutinous Rice Flour and Optimization of Process to Reduce Glutinous Rice Flour Glycemic Index

Objective: To study the effect of ultrasonic treatment on the digestion characteristics and glycemic index (GI) of glutinous rice flour. Methods: With GI value as the index, the effects of four factors, including emulsion concentration, ultrasonic power, ultrasonic time and drying temperature, on the digestibility of glutinous rice flour were studied by single factor test and response surface method. The results showed that ultrasound could transform the components between starches, increase the content of resistant starch, and significantly (P<0.05) reduce the GI value of glutinous rice flour. The GI value of glutinous rice flour decreased to 76.31 (14.22% lower than that of ordinary glutinous rice flour) with 30% emulsion concentration, 400 W ultrasonic power, 4 min ultrasonic time and 49℃, which was similar to the predicted value of the response surface regression equation (76.28), indicating that the regression model could be used to optimize the ultrasonic treatment process of glutinous rice flour. The crystal form of glutinous rice flour was not changed by ultrasonic treatment. Conclusion: This method could improve the digestibility of glutinous rice flour and provide experimental ideas for the further development of low GI glutinous rice flour

Different wildfire types promoted two-step terrestrial plant community change across the Triassic-Jurassic transition

Frequent wildfires associated with emplacement of the Central Atlantic Magmatic Province (CAMP) are thought to have been important drivers of two significant changes in terrestrial plant communities and diversity during the Triassic-Jurassic Mass Extinction (TJME, ca. 201.51 Ma). ​However, it remains to be investigated whether these two changes are potentially related to different wildfire types. To better understand this relationship, we used a new method to reanalyze fossil pollen and spores across the Triassic-Jurassic transition in the Jiyuan Basin from the North China Plate. Results show that two peaks in wildfire frequency experienced different types of wildfires, with each linked to significant changes in plant communities and diversity losses. In the first wildfire peak, canopy fires dominated and are accompanied by significant losses of canopy forming plants, while in the second wildfire peak, ground cover fires dominated accompanied by significant losses of ground cover plants. ​Changes in atmospheric humidity conditions were an important control on the two different wildfire peaks. Relatively humid climatic conditions corresponded to the prevalence of canopy fires and hindered the spread and development of ground cover fires in wet surface conditions. Conversely, relatively arid climatic conditions corresponded with the prevalence of ground cover fires in dry surface environments. Our results provide a potential relationship between terrestrial plant communities and wildfire types, which is important to further understanding of terrestrial environmental and floral changes driven by Large Igneous Provinces

Different wildfire types promoted two-step terrestrial plant community change across the Triassic-Jurassic transition

Frequent wildfires associated with emplacement of the Central Atlantic Magmatic Province (CAMP) are thought to have been important drivers of two significant changes in terrestrial plant communities and diversity during the Triassic-Jurassic Mass Extinction (TJME, ca. 201.51 Ma). ​However, it remains to be investigated whether these two changes are potentially related to different wildfire types. To better understand this relationship, we used a new method to reanalyze fossil pollen and spores across the Triassic-Jurassic transition in the Jiyuan Basin from the North China Plate. Results show that two peaks in wildfire frequency experienced different types of wildfires, with each linked to significant changes in plant communities and diversity losses. In the first wildfire peak, canopy fires dominated and are accompanied by significant losses of canopy forming plants, while in the second wildfire peak, ground cover fires dominated accompanied by significant losses of ground cover plants. ​Changes in atmospheric humidity conditions were an important control on the two different wildfire peaks. Relatively humid climatic conditions corresponded to the prevalence of canopy fires and hindered the spread and development of ground cover fires in wet surface conditions. Conversely, relatively arid climatic conditions corresponded with the prevalence of ground cover fires in dry surface environments. Our results provide a potential relationship between terrestrial plant communities and wildfire types, which is important to further understanding of terrestrial environmental and floral changes driven by Large Igneous Provinces

Constraints on the spacetime metric around seven "bare" AGNs using X-ray reflection spectroscopy

We present the study of a sample of seven "bare" active galactic nuclei (AGN) observed with Suzaku. We interpret the spectrum of these sources with a relativistic reflection component and we employ our model RELXILL_NK to test the Kerr nature of their supermassive black holes. We constrain the Johannsen deformation parameters $\alpha_{13}$ and $\alpha_{22}$, in which the Kerr metric is recovered when $\alpha_{13} = \alpha_{22} = 0$. All our measurements are consistent with the hypothesis that the spacetime geometry around these supermassive objects is described by the Kerr solution. For some sources, we obtain quite strong constraints on $\alpha_{13}$ and $\alpha_{22}$ when compared to those found in our previous studies. We discuss the systematic uncertainties in our tests and the implications of our results.Comment: 15 pages, 12 figures. v2: refereed versio

Dietary patterns and inflammatory bowel disease: a global assessment of eight nutrients by region, gender, and socioeconomic status

BackgroundThis study examines global intake patterns of eight dietary components associated with inflammatory bowel disease (IBD): fruits, non-starchy vegetables, processed meats, unprocessed red meats, saturated fats, monounsaturated fatty acids, omega-6 fatty acids, and dietary fiber. Consumption patterns were analyzed across demographic, geographic, and cultural dimensions, including region, sex, urban–rural residence, and educational level. This analysis reveals disparities in dietary intake and provides insights into the links between diet and IBD risk.MethodsThis study uses meta-analysis to evaluate the relationship between inflammatory bowel disease (IBD) and eight dietary components: fruit, non-starchy vegetables, processed meat, unprocessed red meat, dietary fiber, saturated fat, monounsaturated fatty acids, and omega-6 fatty acids. Drawing on data from the Global Dietary Database (GDD), a Bayesian model was employed to estimate intake levels and uncertainties at global and regional scales, incorporating variables such as education, urbanization, and the Socio-Demographic Index (SDI). The analysis covers global intake trends from 1990 to 2018 across 185 countries, and examines the association between educational attainment and IBD-related nutrient consumption from 1900 to 2015 in 145 countries. Instead of relying on traditional hypothesis testing, the study adopts uncertainty intervals (UIs), which provide probabilistic insights into dietary patterns and their variability across populations.ResultsBetween 1990 and 2018, processed meat intake showed the largest global increase among the eight dietary components, rising by 26% to 29.1 g/day (95% UI: 25.6–33.1). In Asia, unprocessed red meat intake rose by 38% to 53.5 g/day (95% UI: 42.1–67.6), and processed meat increased by 28% to 21.2 g/day (95% UI: 15.6–27.1). Non-starchy vegetable consumption in Central and Eastern Europe and Central Asia grew by 49%, reaching 182.8 g/day (95% UI: 146.2–228). In high-income countries, unprocessed red meat intake increased by 25% to 32.6 g/day (95% UI: 26.4–40.5). Latin America saw a 45% rise in vegetable intake, reaching 130.2 g/day (95% UI: 113.5–150.1), while the Middle East and North Africa reported a 13% increase to 152.1 g/day (95% UI: 129.8–177.4). South Asia experienced the most rapid relative growth in processed meat consumption (56%), reaching 4.6 g/day (95% UI: 2.4–8.2), although absolute intake remained low. In Sub-Saharan Africa, fruit consumption rose by 15%, to 81.5 g/day (95% UI: 71.3–93.5). These results reveal pronounced regional variation in dietary transitions over the past three decades, underscoring the importance of context-specific strategies to address changing dietary risk factors related to IBD.ConclusionThis study found that between 1990 and 2018, processed meat intake increased the most across 185 countries, rising by 26%, mirroring the global rise in IBD burden. The intake of eight dietary components showed significant heterogeneity across global populations, with variations by age, education level, and urbanization. These findings may inform policy interventions aimed at reducing intake in high-risk groups with high consumption of dietary factors linked to IBD, particularly in high-income countries and Asia, where IBD burden is increasing rapidly. The sharp rise in processed and unprocessed red meat intake, combined with long-term underconsumption of fruits, vegetables, and dietary fiber, likely contributes significantly to the rising IBD burden

Pseudonocardians A–C, New Diazaanthraquinone Derivatives from a Deap-Sea Actinomycete Pseudonocardia sp. SCSIO 01299

Pseudonocardians A–C (2–4), three new diazaanthraquinone derivatives, along with a previously synthesized compound deoxynyboquinone (1), were produced by the strain SCSIO 01299, a marine actinomycete member of the genus Pseudonocardia, isolated from deep-sea sediment of the South China Sea. The structures of compounds 1–4 were determined by mass spectrometry and NMR experiments (1H, 13C, HSQC, and HMBC). The structure of compound 1, which was obtained for the first time from a natural source, was confirmed by X-ray analysis. Compounds 1–3 exhibited potent cytotoxic activities against three tumor cell lines of SF-268, MCF-7 and NCI-H460 with IC50 values between 0.01 and 0.21 μm, and also showed antibacterial activities on Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212 and Bacillus thuringensis SCSIO BT01, with MIC values of 1–4 μg mL−1

Identification of disulfidptosis related subtypes, characterization of tumor microenvironment infiltration, and development of DRG prognostic prediction model in RCC, in which MSH3 is a key gene during disulfidptosis

Disulfidptosis is a newly discovered mode of cell death induced by disulfide stress. However, the prognostic value of disulfidptosis-related genes (DRGs) in renal cell carcinoma (RCC) remains to be further elucidated. In this study, consistent cluster analysis was used to classify 571 RCC samples into three DRG-related subtypes based on changes in DRGs expression. Through univariate regression analysis and LASSO-Cox regression analysis of differentially expressed genes (DEGs) among three subtypes, we constructed and validated a DRG risk score to predict the prognosis of patients with RCC, while also identifying three gene subtypes. Analysis of DRG risk score, clinical characteristics, tumor microenvironment (TME), somatic cell mutations, and immunotherapy sensitivity revealed significant correlations between them. A series of studies have shown that MSH3 can be a potential biomarker of RCC, and its low expression is associated with poor prognosis in patients with RCC. Last but not least, overexpression of MSH3 promotes cell death in two RCC cell lines under glucose starvation conditions, indicating that MSH3 is a key gene in the process of cell disulfidptosis. In summary, we identify potential mechanism of RCC progression through DRGs -related tumor microenvironment remodeling. In addition, this study has successfully established a new disulfidptosis-related genes prediction model and discovered a key gene MSH3. They may be new prognostic biomarkers for RCC patients, provide new insights for the treatment of RCC patients, and may inspire new methods for the diagnosis and treatment of RCC patients

Health Consequences Among COVID-19 Convalescent Patients 30 Months Post-Infection in China

The health consequences among COVID-19 convalescent patients 30 months post-infection were described and the potential risk factors were determined. In August 2022 we recruited 217 COVID-19 convalescent patients who had been diagnosed with COVID-19 in February 2020. These convalescent patients were residents of multiple districts in Wuhan, China. All convalescent patients completed a detailed questionnaire, laboratory testing, a 6-min walk test, a Borg dyspnea scale assessment, lung function testing, and had a chest CT. The potential risk factors for health consequences among COVID-19 convalescent patients 30 months post-infection were identified using a multivariate logistic regression model. The majority of convalescent patients were in good overall health and returned to work 30 months post-infection; however, 62.2% of the convalescent patients had long COVID symptoms. The most common symptoms were chest pain, fatigue, and dizziness or headaches. The convalescent patients with severe symptoms had a significantly higher proportion of depression disorder ( P = 0.044) and lower health-related quality of life ( P = 0.034) compared to the convalescent patients with mild symptoms. Compared to convalescent patients who were not vaccinated, convalescent patients who received three vaccines had significantly less fatigue, lower anxiety and depression scores, and had a better health-related quality of life (all P < 0.05). Older age was associated with a higher risk of long COVID (OR = 1.52, 95% CI = 1.16–2.02) and chest CT abnormalities (OR = 1.75, 95% CI = 1.33–2.36). Female gender was associated with a higher risk of anxiety (OR = 3.20, 95% CI = 1.24–9.16) and depression disorders (OR = 2.49, 95% CI = 1.11–5.92). Exercise was associated with a lower risk of anxiety (OR = 0.41, 95% CI = 0.18–0.93). Notably, vaccination protected convalescent patients from developing long COVID symptoms (OR = 0.18, 95% CI = 0.06–0.50), anxiety disorders (OR = 0.22, 95% CI = 0.07–0.71), and depression disorders (OR = 0.33, 95% CI = 0.12–0.92). The majority of COVID-19 convalescent patients were in good overall health 30 months post-infection and returned to work. More attention should be paid to convalescent patients who are older, female, physically inactive, and not vaccinated