Investigation of hydrate slurry flow behaviors in deep-sea pipes with different inclination angles

The marine area is the main direction of the development of oil and gas resources in the world. The pipeline transportation technology of natural gas hydrate slurry plays an important role in the exploitation of marine oil and gas and the exploitation of marine gas hydrate resources. In order to study the influence of pipe inclination on pipeline transportation, population balance model based on hydrate particle aggregation dynamics was coupled with the Eulerian–Eulerian two-fluid multiphase flow model to simulate the flow behaviors of hydrate slurry flow in pipes with different inclination angles. In the study, three variables of inclination, flow rate and initial particle size were considered. The results show that tilted pipes are beneficial to hydrate slurry transport rather than harmful. Meanwhile, higher flow rates and lower initial particle sizes are beneficial for promoting the flow safety of hydrate slurry transport. However, the flow pressure drop of the hydrate slurry increases with the increase of the flow rate and the decrease of the initial particle size, which is not conducive to the economics of mining. The research results in this paper can provide reference for the research of hydrate slurry flow safety and parameter guidance for hydrate solid fluidized mining

Associations of sugar-sweetened beverages intake frequency with physical growth and glucolipid metabolism among children and adolescents

BackgroundChildren and adolescents drink sugar-sweetened beverages (SSBs) frequently. Research has confirmed that SSBs associate with weight gain and overweight or obesity. However, it is unclear whether high SSBs intake associates with abnormal changes in physical growth and glucolipid metabolism before causing adverse health outcomes such as overweight and obesity. Early identification of associated health risks of overconsumption of SSBs have important public health implications. ObjectiveTo investigate the differences in physical growth and glucolipid metabolism between different SSBs intake frequency groups in normal weight children and adolescents aged 6-17 years, and to evaluate the early effects of SSBs intake on physical growth and glycolipid metabolism before causing overweight and obesity, aiming to provide a scientific basis for the prevention and control of childhood overweight and obesity and related chronic diseases, and for the formulation of policies on the control of SSBs consumption. MethodsData were from the Shanghai Diet and Health Survey (SDHS) among primary and secondary school students. The participants were normal weight children and adolescents aged 6-17 years. Propensity scores were calculated according to energy intake and physical activity factors, after stratifying by age and gender. Participants were 1:1 matched with the closest propensity scores in the high-frequency (≥1 time·d−1) and the low-frequency (≤1 time·week−1) SSBs intake groups. The outcome indicators were physical measurements such as height, weight, percent of body fat, and waist circumference, and metabolic indicators such as fasting blood glucose, total triglycerides, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol. Body mass index (BMI) was calculated. Food frequency questionnaire was used to collect SSBs consumption in the past three months through face-to-face interview. A paired t-test was used to compare the differences in physical and glycolipid metabolic indicators between the high-frequency intake group and the low-frequency intake group of SSBs. ResultsA total of 431 pairs were obtained. For children and adolescents in grades 6-9, overall height (difference=2.92 cm, P=0.002), weight (difference=2.53 kg, P=0.003), and waist circumference (difference=1.34 cm, P=0.035) were higher in those who consumed SSBs ≥1 time·d−1 than in those who consumed ≤1 time·week−1. For children and adolescents in grades 10-12, overall weight (difference=2.27 kg, P=0.041) was higher in those who consumed SSBs ≥1 time·d−1 than in those who consumed ≤1 time·week−1. Over 95% of the study subjects reported blood glucose and lipid test results within the normal range; but girls in grades 1-5 who consumed SSBs ≥1 time·d−1 had a higher total cholesterol (difference=0.20 mmol·L−1, P=0.027) and low-density lipoprotein cholesterol (difference=0.19 mmol·L−1, P=0.010) than those who consumed ≤1 time·week−1; boys in grades 6-9 who consumed SSBs ≥1 time·d−1 had a lower high-density lipoprotein cholesterol (difference=-0.10 mmol·L−1, P=0.039) than those who consumed ≤1 time·week−1. ConclusionHigh-frequency intake of SSBs may be associated with higher total cholesterol and low-density lipoprotein cholesterol in normal weight children and adolescents in grades 1-5, and higher weight in normal weight children and adolescents in grades 6-12. There is an urgent need to educate children and adolescents about nutritional health, enhance their ability to make healthy food and beverage choices, and take early interventions to control the intake of SSBs in children

Non-destructive 3D Microtomography of Cerebral Angioarchitecture Changes Following Ischemic Stroke in Rats Using Synchrotron Radiation

A better understanding of functional changes in the cerebral microvasculature following ischemic injury is essential to elucidate the pathogenesis of stroke. Up to now, the simultaneous depiction and stereological analysis of 3D micro-architectural changes of brain vasculature with network disorders remains a technical challenge. We aimed to explore the three dimensional (3D) microstructural changes of microvasculature in the rat brain on 4, 6 hours, 3 and 18 days post-ischemia using synchrotron radiation micro-computed tomography (SRμCT) with a per pixel size of 5.2 μm. The plasticity of angioarchitecture was distinctly visualized. Quantitative assessments of time-related trends after focal ischemia, including number of branches, number of nodes, and frequency distribution of vessel diameter, reached a peak at 6 h and significantly decreased at 3 days and initiated to form cavities. The detected pathological changes were also proven by histological tests. We depicted a novel methodology for the 3D analysis of vascular repair in ischemic injury, both qualitatively and quantitatively. Cerebral angioarchitecture sustained 3D remodeling and modification during the healing process. The results might provide a deeper insight into the compensatory mechanisms of microvasculature after injury, suggesting that SRμCT is able to provide a potential new platform for deepening imaging pathological changes in complicated angioarchitecture and evaluating potential therapeutic targets for stroke

The Generalizability of Older Adult Self-Report (OASR) Syndromes of Psychopathology Across 20 Societies

OBJECTIVES: As the world population ages, psychiatrists will increasingly need instruments for measuring constructs of psychopathology that are generalizable to diverse elders. The study tested whether syndromes of co-occurring problems derived from self-ratings of psychopathology by US elders would fit self-ratings by elders in 19 other societies. METHODS/DESIGN: The Older Adult Self-Report (OASR) was completed by 12,826 60- to 102-year-olds in 19 societies from North and South America, Asia, and Eastern, Northern, Southern, and Western Europe, plus the US. Individual and multi-group confirmatory factor analyses (CFAs) tested the fit of the 7-syndrome OASR model, consisting of the Anxious/Depressed, Worries, Somatic Complaints, Functional Impairment, Memory/Cognition Problems, Thought Problems, and Irritable/Disinhibited syndromes. RESULTS: In individual CFAs, the primary model fit index showed good fit for all societies, while the secondary model fit indices showed acceptable to good fit. The items loaded strongly on their respective factors, with a median item loading of .63 across the 20 societies; and 98.7% of the loadings were statistically significant. In multi-group CFAs, 98% of items demonstrated approximate or full metric invariance. Fifteen percent of items demonstrated approximate or full scalar invariance and another 59% demonstrated scalar invariance across more than half of societies. CONCLUSIONS: The findings supported the generalizability of OASR syndromes across societies. The seven syndromes offer empirically-based clinical constructs that are relevant for elders of different backgrounds. They can be used to assess diverse elders, and as a taxonomic framework to facilitate communication, services, research and training in geriatric psychiatry. This article is protected by copyright. All rights reserved

Rubber Identification Based on Blended High Spatio-Temporal Resolution Optical Remote Sensing Data: A Case Study in Xishuangbanna

As an important economic resource, rubber has rapidly grown in Xishuangbanna of Yunnan Province, China, since the 1990s. Tropical rainforests have been replaced by extensive rubber plantations, which has resulted in ecological problems such as the loss of biodiversity and local water shortages. It is vitally important to accurately map the rubber plantations in this region. Although several rubber mapping methods have been proposed, few studies have investigated methods based on optical remote sensing time series data with high spatio-temporal resolution due to the cloudy and foggy weather conditions in this area. This study presented a rubber plantation identification method that used spatio-temporal optical remote sensing data fusion technology to obtain vegetation index data at high spatio-temporal resolution within the optical remote sensing window in Xishuangbanna. The analysis of the proposed method shows that (1) fused optical remote sensing data with high spatio-temporal resolution could map the rubber distribution with high accuracy (overall accuracy of up to 89.51% and kappa of 0.86). (2) Fused indices have high R2 (R2 greater than 0.8, where R is the correlation coefficient) with the indices that were derived from the Landsat observed data, which indicates that fusion results are dependable. However, the fusion accuracy is affected by terrain factors including elevation, slope, and slope aspects. These factors have obvious negative effects on the fusion accuracy of high spatio-temporal resolution optical remote sensing data: the highest fusion accuracy occurred in areas with elevations between 1201 and 1400 m.a.s.l., and the lowest accuracy occurred in areas with elevations less than 600 m.a.s.l. For the 5 fused time series indices (normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), normalized difference moisture index (NDMI), normalized burn ratio (NBR), and tasseled cap angle (TCA)), the fusion accuracy decreased with increasing slope, and increasing slope had the least impact on the EVI, but the greatest negative impact on the NDVI; the slope aspect had a limited influence on the fusion accuracies of the 5 time series indices, but fusion accuracy was lowest on the northwest slope. (3) EVI had the highest accuracy of rubber plantation classification among the 5 time series indices, and the overall classification accuracies of the time series EVI for the four different years (2000, 2005, 2010, and 2015) reached 87.20% (kappa 0.82), 86.91% (kappa 0.81), 88.85% (kappa 0.84), and 89.51% (kappa 0.86), respectively. The results indicate that the method is a promising approach for rubber plantation mapping and the detection of changes in rubber plantations in this tropical area

Investigation of hydrate slurry flow behaviors in deep-sea pipes with different inclination angles

International audienceThe marine area is the main direction of the development of oil and gas resources in the world. The pipeline transportation technology of natural gas hydrate slurry plays an important role in the exploitation of marine oil and gas and the exploitation of marine gas hydrate resources. In order to study the influence of pipe inclination on pipeline transportation, population balance model based on hydrate particle aggregation dynamics was coupled with the Eulerian–Eulerian two-fluid multiphase flow model to simulate the flow behaviors of hydrate slurry flow in pipes with different inclination angles. In the study, three variables of inclination, flow rate and initial particle size were considered. The results show that tilted pipes are beneficial to hydrate slurry transport rather than harmful. Meanwhile, higher flow rates and lower initial particle sizes are beneficial for promoting the flow safety of hydrate slurry transport. However, the flow pressure drop of the hydrate slurry increases with the increase of the flow rate and the decrease of the initial particle size, which is not conducive to the economics of mining. The research results in this paper can provide reference for the research of hydrate slurry flow safety and parameter guidance for hydrate solid fluidized mining

The Interactive Effects of Severe Vitamin D Deficiency and Iodine Nutrition Status on the Risk of Thyroid Disorder in Pregnant Women

Thyroid dysfunction is associated with both vitamin D deficiency and iodine; however, it is unclear whether they interact. This study aimed to investigate whether and to what extent the interactions between vitamin D and iodine contribute to the risk of thyroid disorder. Participants (n = 4280) were chosen using multistage, stratified random sampling from Shanghai. Fasting blood was drawn for the 25(OH)D and thyroid parameter tests. Spot urine samples were gathered to test for urine iodine. To evaluate the interactive effects of vitamin D and iodine, crossover analysis was carried out. Pregnant women with a high urinary iodine concentration (UIC) and severe vitamin D deficiency had a significantly higher risk of thyrotropin receptor antibody (TrAb) positivity (odds ratio = 2.62, 95% confidence interval (CI): 1.32, 5.22) in the first trimester. Severe vitamin D deficiency and high UIC interacted positively for the risk of TrAb positivity (relative excess risk due to interaction = 1.910, 95%CI: 0.054, 3.766; attributable proportion = 0.700, 95%CI: 0.367, 1.03). Severe vitamin D deficiency combined with excess iodine could increase the risk of TrAb positivity in pregnant women in the first trimester

Controlled Synthesis of Polyfluorenes via Kumada Catalyst Transfer Polycondensation with Ni(acac)₂/dppp as the Catalyst

A new catalyst system, i.e., nickel acetylacetonate/1,3-bis­(diphenylphosphino)­propane (Ni­(acac)₂/dppp), was explored to catalyze the Kumada catalyst transfer polycondensation (KCTP) of three fluorene monomers with different substituents at 9-position. The “living” nature of the polymerization was confirmed by polymerization kinetic studies, “monomer addition” experiment and block copolymerizations. As a result, poly­(9,9-dioctylfluorene)­s (PF8s) with the number-average molecular weights (<i>M</i>_ns) in the range 2.8–62.2 kDa and polydispersity indices (PDIs) of ∼1.20 were successfully synthesized in a controlled manner. The syntheses of fluorene-fluorene and fluorene-thiophene diblock copolymers with <i>M</i>_ns up to 46 kDa were also demonstrated. A complex, i.e. Ni­(dppp)­(acac)₂, with an octahedral coordination geometry was isolated and confirmed by X-ray crystallographic analysis. The polymerization experiments indicated that the in situ formed Ni­(dppp)­(acac)₂ should be the active catalyst. To the best of our knowledge, this is the first report on the controlled synthesis of polyfluorenes (PFs) via KCTP