Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it...Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.展开更多
目的评估癌症、心脑血管疾病、糖尿病及慢性呼吸系统疾病(以下简称“四大慢病”)的主要危险因素及相关危险因素暴露的疾病负担。方法本研究数据来源于2019年全球疾病负担研究(Global Burden of Disease Study,GBD)数据库,通过获取2019...目的评估癌症、心脑血管疾病、糖尿病及慢性呼吸系统疾病(以下简称“四大慢病”)的主要危险因素及相关危险因素暴露的疾病负担。方法本研究数据来源于2019年全球疾病负担研究(Global Burden of Disease Study,GBD)数据库,通过获取2019年我国居民四大慢病的死亡病例数和伤残调整寿命年(disability-adjusted life years,DALYs),分析四大慢病归因于相关危险因素暴露的比例。结果烟草暴露是造成恶性肿瘤疾病负担最主要的危险因素,导致的DALYs占比达31.4%;心脑血管疾病的首要危险因素是高收缩压,导致的DALYs占比达55.6%。四大慢病的共同危险因素有烟草暴露、空气污染和高身体质量指数,其中烟草暴露在恶性肿瘤和慢性呼吸系统疾病中归因风险比例最高,饮食相关危险因素、饮酒和体力活动不足与恶性肿瘤、心脑血管疾病及糖尿病密切相关。对主要恶性肿瘤疾病负担的归因分析结果显示,烟草暴露归因风险比例最高的是肺癌,其次是食管癌、胃癌、肝癌及结直肠癌。结论烟草暴露、空气污染和高身体质量指数是我国居民癌症等四大慢病的共同危险因素,能为四大慢病高风险人群筛选提供重要依据。展开更多
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030003).
文摘Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.
文摘目的评估癌症、心脑血管疾病、糖尿病及慢性呼吸系统疾病(以下简称“四大慢病”)的主要危险因素及相关危险因素暴露的疾病负担。方法本研究数据来源于2019年全球疾病负担研究(Global Burden of Disease Study,GBD)数据库,通过获取2019年我国居民四大慢病的死亡病例数和伤残调整寿命年(disability-adjusted life years,DALYs),分析四大慢病归因于相关危险因素暴露的比例。结果烟草暴露是造成恶性肿瘤疾病负担最主要的危险因素,导致的DALYs占比达31.4%;心脑血管疾病的首要危险因素是高收缩压,导致的DALYs占比达55.6%。四大慢病的共同危险因素有烟草暴露、空气污染和高身体质量指数,其中烟草暴露在恶性肿瘤和慢性呼吸系统疾病中归因风险比例最高,饮食相关危险因素、饮酒和体力活动不足与恶性肿瘤、心脑血管疾病及糖尿病密切相关。对主要恶性肿瘤疾病负担的归因分析结果显示,烟草暴露归因风险比例最高的是肺癌,其次是食管癌、胃癌、肝癌及结直肠癌。结论烟草暴露、空气污染和高身体质量指数是我国居民癌症等四大慢病的共同危险因素,能为四大慢病高风险人群筛选提供重要依据。
