Temperature-dependent structure of an intermetallic ErPd2_2Si2_2 single crystal: A combined synchrotron and in-house X-ray diffraction study

We have grown intermetallic ErPd$_2$Si$_2$ single crystals employing laser-diodes with the floating-zone method. The temperature-dependent crystallography was determined using synchrotron and in-house X-ray powder diffraction measurements from 20 to 500 K. The diffraction patterns fit well with the tetragonal $I$4/$mmm$ space group (No. 139) with two chemical formulas within one unit cell. Our synchrotron X-ray powder diffraction study shows that the refined lattice constants are $a$ = 4.10320(2) {\AA}, $c$ = 9.88393(5) {\AA} at 298 K and $a$ = 4.11737(2) {\AA}, $c$ = 9.88143(5) {\AA} at 500 K, resulting in the unit-cell volume $V$ = 166.408(1) {\AA}$^3$ (298 K) and 167.517(2) {\AA}$^3$ (500 K). In the whole studied temperature range, we did not find any structural phase transition. Upon cooling, the lattice constants a and c are shortened and elongated, respectively.Comment: 5 Figures, 4 Table

Diverse associations between pancreatic intra-, inter-lobular fat and the development of type 2 diabetes in overweight or obese patients

Pancreatic fat is associated with obesity and type 2 diabetes mellitus (T2DM); however, the relationship between different types of pancreatic fat and diabetes status remains unclear. Therefore, we aimed to determine the potential of different types of pancreatic fat accumulation as a risk factor for T2DM in overweight or obese patients. In total, 104 overweight or obese patients were recruited from January 2020 to December 2022. The patients were divided into three groups: normal glucose tolerance (NGT), impaired fasting glucose or glucose tolerance (IFG/IGT), and T2DM. mDixon magnetic resonance imaging (MRI) was used to detect pancreatic fat in all three groups of patients. The pancreatic head fat (PHF), body fat (PBF), and tail fat (PTF) in the IFG/IGT group were 21, 20, and 31% more than those in the NGT group, respectively. PHF, PBF, and PTF were positively associated with glucose metabolic dysfunction markers in the NGT group, and inter-lobular fat volume (IFV) was positively associated with these markers in the IFG/IGT group. The areas under the receiver operating characteristic curves for PHF, PBF, and PTF (used to evaluate their diagnostic potential for glucose metabolic dysfunction) were 0.73, 0.73, and 0.78, respectively, while those for total pancreatic volume (TPV), pancreatic parenchymal volume, IFV, and IFV/TPV were 0.67, 0.67, 0.66, and 0.66, respectively. These results indicate that intra-lobular pancreatic fat, including PHF, PTF, and PBF, may be a potential independent risk factor for the development of T2DM. Additionally, IFV exacerbates glucose metabolic dysfunction. Intra-lobular pancreatic fat indices were better than IFV for the diagnosis of glucose metabolic dysfunction

Novel loci and pathways significantly associated with longevity

Only two genome-wide significant loci associated with longevity have been identified so far, probably because of insufficient sample sizes of centenarians, whose genomes may harbor genetic variants associated with health and longevity. Here we report a genome-wide association study (GWAS) of Han Chinese with a sample size 2.7 times the largest previously published GWAS on centenarians. We identified 11 independent loci associated with longevity replicated in Southern-Northern regions of China, including two novel loci (rs2069837-IL6; rs2440012-ANKRD20A9P) with genome-wide significance and the rest with suggestive significance (P < 3.65 × 10(−5)). Eight independent SNPs overlapped across Han Chinese, European and U.S. populations, and APOE and 5q33.3 were replicated as longevity loci. Integrated analysis indicates four pathways (starch, sucrose and xenobiotic metabolism; immune response and inflammation; MAPK; calcium signaling) highly associated with longevity (P ≤ 0.006) in Han Chinese. The association with longevity of three of these four pathways (MAPK; immunity; calcium signaling) is supported by findings in other human cohorts. Our novel finding on the association of starch, sucrose and xenobiotic metabolism pathway with longevity is consistent with the previous results from Drosophilia. This study suggests protective mechanisms including immunity and nutrient metabolism and their interactions with environmental stress play key roles in human longevity

Novel loci and pathways significantly associated with longevity

Only two genome-wide significant loci associated with longevity have been identified so far, probably because of insufficient sample sizes of centenarians, whose genomes may harbor genetic variants associated with health and longevity. Here we report a genome-wide association study (GWAS) of Han Chinese with a sample size 2.7 times the largest previously published GWAS on centenarians. We identified 11 independent loci associated with longevity replicated in Southern-Northern regions of China, including two novel loci (rs2069837-IL6; rs2440012-ANKRD20A9P) with genome-wide significance and the rest with suggestive significance (P < 3.65 × 10⁻⁵). Eight independent SNPs overlapped across Han Chinese, European and U.S. populations, and APOE and 5q33.3 were replicated as longevity loci. Integrated analysis indicates four pathways (starch, sucrose and xenobiotic metabolism; immune response and inflammation; MAPK; calcium signaling) highly associated with longevity (P ≤ 0.006) in Han Chinese. The association with longevity of three of these four pathways (MAPK; immunity; calcium signaling) is supported by findings in other human cohorts. Our novel finding on the association of starch, sucrose and xenobiotic metabolism pathway with longevity is consistent with the previous results from Drosophilia. This study suggests protective mechanisms including immunity and nutrient metabolism and their interactions with environmental stress play key roles in human longevity.This is the publisher’s final pdf. The published article is copyrighted by the author(s) and published by Nature Publishing Group. The published article can be found at: http://www.nature.com/articles/srep2124

A study of the increase in subsurface freshwater on coral islands by slope seepage control: Experiment and modeling

Fresh groundwater lenses are important resources for local inhabitants and ecosystems in coral islands. In view of the complexity of the coral islands, it is necessary to seek the measures of low-cost, effective and less impact on the stability and the ecosystem to increase freshwater reserves. Based on the sandbox experiments and numerical simulations, this study proposes an engineering measure to increase freshwater reserves by laying impermeable materials on the slope of an island. The effects of the measure on fresh groundwater lenses formation and different factors on increasing freshwater reserves in slope seepage prevention are evaluated. The practical feasibility of this measure is also discussed in case of the Yongxing Island. The results show that the slope seepage control increases the freshwater reserves by changing the groundwater flow field to increase the freshwater head. The stabilization time of the freshwater lens is also increased. After laying impermeable materials on slope of the sandbox (with the length, width and height of 50 cm, 5 cm and 35 cm, respectively), the maximum thickness of freshwater lens increases from 13.7 cm to 24.9 cm, the freshwater reserves increases from 561.8 cm3 to 1592.3 cm3, and stabilization time increases from 120 min to 150 min, respectively. The increased freshwater reserves develop with the increasing rainfall intensity and slope impermeable depth, and also extend with the decreasing permeability of coral sand and impermeable materials. The Yongxing Island is taken as an example, and laying impermeable materials with a depth of 2 m on the slope will increase the freshwater reserves from 3.4×106 m3 to 4.4×106 m3 in the next 30 years, increasing the original reserve by 1/4. This study can provide theoretical support and practical guidance for sustainable groundwater management and water resources security in island areas of China

Structural optimization design of semi-rigid base asphalt pavement using modulus matching criterion and multi-indicator range analysis

Damage to semi-rigid base asphalt pavement is related to improper matching of the pavement structure moduli. This study mainly focused on the modulus matching of structural layers and the development of a pavement structure optimization method. First, the modulus loss of existing pavement structures was analysed, and a three-dimensional finite element model was established based on the existing pavement. Second, the influence of the modulus of each structural layer on the mechanical response indicators and fatigue life was analysed. Based on the results, a pavement structure design method using the smoothness of the stress-strain curve as the modulus matching criterion of the structural layers was proposed. And it was found that a strain convex point was present and that the stress mutation between the structural layers was significant when the modulus matching of the pavement structure was reasonable. Further, the evaluation indicators were divided into two groups, namely, mechanical indicators and fatigue life indicators. And it was proposed an optimized pavement structure design method based on modulus matching and multi-indicator range analysis. Finally, the optimal modulus combination of pavement structure was determined by this method. The research systematically studied the influence of the modulus of each structural layer on the mechanical response and fatigue life of the pavement, and proposed the concept and specific executive criteria of modulus matching for the first time. Meanwhile, it also provided an effective optimization method for pavement structure design

Experimental study on the effect of subsurface freshwater-saltwater mixing on the permeability of coral sand

Objective The permeability of coral sand is the key factor determining the groundwater reserves of coral islands. For a long time, the research on the influence of different salinity filtrates on the permeability of coral sand during the formation of freshwater lenses is quiet few. Methods In this study, three kinds of solutions with different salinities were designed to represent freshwater, transition zone water and seawater to conduct dissolution and permeation tests on coral sand. Based on X-ray diffraction analysis and PHREEQC reverse simulation, the possible causes of water-rock interactions and permeability changes in coral sand in different salinity solutions were discussed. Results Results showed that the permeability of coral sand was highly related to its dissolution in water bodies. The higher the salinity of the solution, the stronger the dissolution and the greater the permeability coefficient of the coral sand. The permeability coefficient of coral sand was almost unchanged in pure water. In saltwater, coral sand has undergone water-rock interactions, including carbonate dissolution and Na+-Ca2+ ion exchange, and the water-rock interaction is stronger with increasing salinity. After 360 hours of reaction under NaCl solutions with concentrations of 0.2 mol/L and 0.4 mol/L, the coral sand permeability coefficient changed from 0.58 m/d to 0.64 m/d and 0.74 m/d, respectively. It was inferred that dissolution could increase the overall porosity and thus the permeability coefficient by changing the sand particle size. Conclusion The results provide a scientific reference for the accurate assessment of freshwater reserves and the sustainable development of water resources on coral islands

Persistent oxygen-glucose deprivation induces astrocytic death through two different pathways and calpain-mediated proteolysis of cytoskeletal proteins during astrocytic oncosis

Astrocytes are thought to play a role in the maintenance of homeostasis and the provision of metabolic substrates for neurons as well as the coupling of cerebral blood flow to neuronal activity. Accordingly, astrocytic death due to various types of injury can critically influence neuronal survival. The exact pathway of cell death after brain ischemia is under debate. In the present study, we used astrocytes from rat primary culture treated with persistent oxygen-glucose-deprivation (OGD) as a model of ischemia to examine the pathway of cell death and the relevant mechanisms. We observed changes in the cellular morphology, the energy metabolism of astrocytes, and the percentage of apoptosis or oncosis of the astrocytes induced by OGD. Electron microscopy revealed the co-existence of ultrastructural features in both apoptosis and oncosis in individual cells. The cellular ATP content was gradually decreased and the percentages of apoptotic and oncotic cells were increased during OGD. After 4h of OGD. ATP depletion to less than 35\% of the control was observed, and oncosis became the primary pathway for astrocytic death. Increased plasma membrane permeability due to oncosis was associated with increased calpain-mediated degradation of several cytoskeletal proteins, including paxillin, vinculin, vimentin and GFAP. Pre-treatment with the calpain inhibitor 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606) could delay the OGD-induced astrocytic oncosis. These results suggest that there is a narrow range of ATP that determines astrocytic oncotic death induced by persistent OGD and that calpain-mediated hydrolysis of the cytoskeletal-associated proteins may contribute to astrocytes oncosis. (C) 2010 Elsevier Ireland Ltd. All rights reserved