Thyroid volume, goiter prevalence, and selenium levels in an iodine-sufficient area: a cross-sectional study

Abstract Background Selenium (Se) is a necessary element for the biosynthesis of thyroid hormones. We investigated the relationship between selenium status, thyroid volume, and goiter in a cross-sectional study in an iodine-sufficient area. Methods We selected residents of Chengdu (over 18 years old and living in the city for more than 5 years) using a stratified cluster sampling technique. Fifteen hundred subjects were selected for the study, which involved a questionnaire survey, physical examination, thyroid ultrasound, serum thyroid function test, and determination of serum selenium level. Thyroid volume was calculated from the thickness, width, length, and a corrective factor for each lobe. Ultimately, 1,205 subjects completed the investigation and were included in our study. Additionally, 80 school-age children were selected to provide urine samples for urinary iodine analysis. We analyzed the data using appropriate nonparametric and parametric statistical tests. Results The median urinary iodine value was 184 μg/L in school-age children, indicating iodine sufficiency. The median serum selenium level of the 1,205 subjects was 52.63 (interquartile range [IQR] : 40.40-67.00) μg/L. The median thyroid volume was 9.93 (IQR: 7.71-12.57) mL; both log-transformed serum selenium and log-transformed thyroid volume were Gaussian distributions (P = .638 and P = .046, respectively). The prevalences of goiter and thyroid nodules were 8.8% and 18.6%. The prevalences of positive thyroid autoantibodies, thyroperoxidase autoantibodies and thyroglobulin autoantibodies were 16.7%, 12.0%, and 11.1%, respectively. In the general linear regression model, there were positive associations between serum selenium and age, and body mass index. We found no association between serum selenium and thyroid-stimulating hormone. In simple linear regression analyses, we found no association between thyroid volume and serum selenium. There were no significant differences in serum selenium between persons with or without goiter. Serum selenium was not a risk factor for goiter. Conclusion In our study population, serum selenium was neither associated with thyroid volume nor with goiter in an iodine-sufficient area. More studies should be conducted by following non-goitrous persons over time and monitoring their selenium status. </jats:sec

Analysis of bryophyte species diversity in three northeastern provinces of China and the Korean Peninsula

The three northeastern provinces and the Korean Peninsula are geographically and climatically diverse, and the geographical regions have continuously formed relatively unique flora. This paper collected through the national and provincial list of bryophytes, the specimens in the online herbarium, recently published bryophytes papers and bryophytes information recorded in field investigation in certain areas. Quantitative statistical analysis of plant species or taxa data was carried out by traditional methods. In order to clarify the species diversity and species genetic relationship of bryophytes in the study area, a preliminary study was conducted to explain the flora pattern and formation mechanism. There are 1,006 species of bryophytes belonging to 305 genera and 107 families in the three provinces of Northeast China, and there are 1,119 species of bryophytes belonging to 368 genera and 126 families in the Korean Peninsula. In addition, 477 new distribution records of bryophytes in the three northeastern provinces were supplemented. The dominant families and genera of bryophyte in the Korean Peninsula and the three northeastern provinces are highly similar, and the species richness of mosses and liverworts in the two study areas is dominated by families containing 2–10 species and single-species genera. According to a similarity analysis of family, genus and species, there are 541 species of bryophytes belonging to 269 genera and 102 families in the study area. The three northeastern provinces and the Korean Peninsula are rich in bryophytes, and are mainly distributed in temperate zones. Therefore, the similarity between Heilongjiang Province and Jilin Province in the three northeastern provinces is higher, while the similarity between Jilin Province, Liaoning Province and the Korean Peninsula is higher, indicating that the adjacent areas may have a common evolutionary origin or show evolutionary convergence. Compared with the Korean Peninsula, the proportion of tropical distribution and East Asian distribution in the three northeastern provinces is slightly higher. This study analyses the characteristics, similarity feature and floristic composition of bryophyte species and provides background information on bryophyte biodiversity conservation in the study area, which is highly important for the protection of bryophyte diversity and the promotion of basic data sharing

High-Power and Ultralong-Life Aqueous Zinc-Ion Hybrid Capacitors Based on Pseudocapacitive Charge Storage

© 2019, © 2019, The Author(s). Rechargeable aqueous zinc-ion hybrid capacitors and zinc-ion batteries are promising safe energy storage systems. In this study, amorphous RuO2·H2O for the first time was employed to achieve fast and ultralong-life Zn2+ storage based on a pseudocapacitive storage mechanism. In the RuO2·H2O||Zn zinc-ion hybrid capacitors with Zn(CF3SO3)2 aqueous electrolyte, the RuO2·H2O cathode can reversibly store Zn2+ in a voltage window of 0.4–1.6 V (vs. Zn/Zn2+), delivering a high discharge capacity of 122 mAh g−1. In particular, the zinc-ion hybrid capacitors can be rapidly charged/discharged within 36 s with a very high power density of 16.74 kW kg−1 and a high energy density of 82 Wh kg−1. Besides, the zinc-ion hybrid capacitors demonstrate an ultralong cycle life (over 10,000 charge/discharge cycles). The kinetic analysis elucidates that the ultrafast Zn2+ storage in the RuO2·H2O cathode originates from redox pseudocapacitive reactions. This work could greatly facilitate the development of high-power and safe electrochemical energy storage.[Figure not available: see fulltext.]

Control System Based on Anode Offgas Recycle for Solid Oxide Fuel Cell System

The conflicting operation objectives between rapid load following and the fuel depletion avoidance as well as the strong interactions between the thermal and electrical parameters make the SOFC system difficult to control. This study focuses on the design of the decoupling control for the thermal and electrical characteristics of the SOFC system through anode offgas recycling (AOR). The decoupling control system can independently manipulate the thermal and electrical parameters, which interact with one another in most cases, such as stack temperatures, burner temperature, system current, and system power. Under the decoupling control scheme, the AOR is taken as a manipulation variable. The burner controller maintains the burner temperature without being affected by abrupt power change. The stack temperature controller properly coordinates with the burner temperature controller to independently modulate the stack thermal parameters. For the electrical problems, the decoupling control scheme shows its superiority over the conventional controller in alleviating rapid load following and fuel depletion avoidance. System-level simulation under a power-changing case is performed to validate the control freedom between the thermal and electrical characteristics as well as the stability, efficiency, and robustness of the novel system control scheme

Surgical outcome of hepatocellular carcinoma patients with biliary tumor thrombi

<p>Abstract</p> <p>Background</p> <p>To investigate the surgical outcome of hepatocellular carcinoma (HCC) patients with biliary tumor thrombi (BTT).</p> <p>Methods</p> <p>Surgical outcome of 27 HCC patients with BTT (group I) were compared with randomly selected HCC patients without BTT (group II; n = 270).</p> <p>Results</p> <p>One patient in group I died of hepatic failure within 30 days after resection. The 1-, 3- and 5-year cumulative survival rates of group I were 70.3%, 25.9%, and 7.4%, respectively; these were significantly lower than those of group II (90.6%, 54.0%, and 37.7%) (<it>P <</it>0.001). The rates of early recurrence (≤ 1 year) after resection were significantly higher in group I than group II (70.3% vs. 34.8%) (<it>P </it>< 0.001).</p> <p>Conclusion</p> <p>HCC patients with BTT had a worse prognosis after resection than those without BTT. Resection should be considered for these tumors given the lack of effective alternative therapies.</p