624 research outputs found

    Analytical Model for Multi-Hazard Resilient Prefabricated Concrete Frame Considering Earthquake and Column Removal Scenarios

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    Research on multi-hazard prevention and mitigation in building structures is the most recent developing trend in civil engineering. In this study, an analytical model is proposed to calculate the structural resistance of a type of multi-hazard resilient prefabricated concrete (MHRPC) frame under earthquake and column removal scenarios. The MHRPC frame is assembled using prefabricated RC beams and columns, unbonded post-tensioning (PT) tendons, energy-dissipating steel angles, and large rotational shear plates. According to the experimental results, the MHRPC frame exhibits the features of low damage and self-centering under seismic loading. Meanwhile, when subjected to column removal scenarios, the MHRPC frame is proven to demonstrate a high progressive collapse resistance. In order to calculate the seismic and progressive collapse resistance of the MHRPC frame, analytical models for the critical components in the MHRPC frame (PT tendons and steel angles) are compared and selected based on the experimental results and numerical simulations. Furthermore, calculation methods for the seismic and progressive collapse resistance of the MHRPC frame specimens are proposed. The calculation results are validated using the experimental results. This study could provide a reference for the design of MHRPC frame structures, considering both earthquake and progressive collapse

    SEC24A deficiency lowers plasma cholesterol through reduced PCSK9 secretion.

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    The secretory pathway of eukaryotic cells packages cargo proteins into COPII-coated vesicles for transport from the endoplasmic reticulum (ER) to the Golgi. We now report that complete genetic deficiency for the COPII component SEC24A is compatible with normal survival and development in the mouse, despite the fundamental role of SEC24 in COPII vesicle formation and cargo recruitment. However, these animals exhibit markedly reduced plasma cholesterol, with mutations in Apoe and Ldlr epistatic to Sec24a, suggesting a receptor-mediated lipoprotein clearance mechanism. Consistent with these data, hepatic LDLR levels are up-regulated in SEC24A-deficient cells as a consequence of specific dependence of PCSK9, a negative regulator of LDLR, on SEC24A for efficient exit from the ER. Our findings also identify partial overlap in cargo selectivity between SEC24A and SEC24B, suggesting a previously unappreciated heterogeneity in the recruitment of secretory proteins to the COPII vesicles that extends to soluble as well as trans-membrane cargoes. DOI:http://dx.doi.org/10.7554/eLife.00444.001

    Pharmacokinetic Interaction between Magnolol and Piperine in Rats

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    Purpose: To investigate the pharmacokinetic mechanism of interaction between magnolol and piperine when co-administered to rats.Methods: The rats were divided into five groups as follows: magnolol group (625 mg/kg); low dose of piperine group (20 mg/kg); high dose of piperine group (40 mg/kg); low dose of piperine + magnolol group; or high dose of piperine + magnolol group. Plasma samples were collected at regular time intervals after administration of a single dose of magnolol (625 mg/kg, p.o.) alone or piperine (20 or 40 mg/kg, p.o.) in the presence or absence of magnolol (625 mg/kg, p.o.). The concentrations of magnolol and piperine in plasma were measured by a validated high performance liquid chromatography (HPLC) method.Results: Compared with control, the groups given magnolol alone, concomitant administration of piperine and magnolol resulted in significant decrease (p < 0.01) in the AUC and Cmax of magnolol. Interestingly, compared with administration of piperine alone (20 mg/kg), co-administration with magnolol did not significantly (p > 0.05) alter the pharmacokinetic parameters of piperine. However, at high dose (40 mg/kg) of piperine, Cmax of piperine significantly decreased from 4.30 ± 1.47 to 2.50 ± 0.78 μg/mL (p < 0.05).Conclusion: Co-administration of magnolol and piperine decreases plasma concentration of either drug in rats, suggesting that concurrent use of magnolol with piperine or piperine-containing diets would require close monitoring for potential interactions.Keywords: Magnolol, Piperine, Pharmacokinetic interaction, Co administratio

    Decreased CD8+CD28+/CD8+CD28– T cell ratio can sensitively predict poor outcome for patients with complicated Crohn disease

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    Crohn disease (CD) with complications such as penetrating, stricturing, and perianal disease is called complicated CD. The aim of this study is to test the efficiency with which the CD8+CD28+/CD8+CD28– cell balance can predict a subsequent active stage in patients with newly diagnosed complicated CD. Seventeen patients with complicated CD and 48 CD patients with no complications were enrolled. Blood CD8+ T cells were tested from all of the 65 newly diagnosed CD patients upon enrollment. The potential risk factors were compared between the 2 groups. A 30-week follow-up was performed, and the efficiency of the CD8+ cell balance at predicting active CD was analyzed using receiver- operating characteristic curves. The cumulative remission lasting rates (CRLRs) were analyzed using the Kaplan–Meier method. Compared with the control CD group, patients with complicated CD were predominantly male and younger in age; they also had lower body mass indices (BMIs), higher Crohn disease activity indices (CDAIs), higher immunosuppressant and steroid prescription rates, and significantly higher surgical rates. The CD8+CD28+/CD8+CD28– balance was associated with BMI, CDAI, steroids, and surgery. The CD8+CD28+/CD8+CD28– ratios were significantly lower at week 0 and on the 6th, 22nd, and 30th week during follow- up with a shorter lasting time of remission for the complicated CD patients. The CD8+CD28+/CD8+CD28– ratio could accurately predict the active stage for the patients with complicated CD, and the highest sensitivity (89.2%) and specificity (85.3%) were found when the ratio was 1.03. Treatment with steroids and surgery, along with a significantly lower CD8+CD28+/CD8+CD28– ratio and lower CRLRs, was closely related to a worse outcome for the patients with complicated CD. Patients requiring steroids and surgery experience more severe disease activity and thus a disequilibrated immunological balance, which could be the main reason for a decreased CD8+CD28+/CD8+CD28– ratio. This ratio can sensitively predict the active stage for patients with complicated CD, and more care should be taken when this ratio is <1.03

    25-hydroxyvitamin D levels in children of different ages and with varying degrees of Helicobacter pylori infection and immunological features

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    BackgroundHelicobacter pylori (HP) is a major cause of upper digestive tract diseases. However, the relationship between HP infection and 25-hydroxyvitamin D [25(OH)D] levels in children has not been fully elucidated. This study investigated the levels of 25(OH)D in children of different ages and with varying degrees of HP infection and immunological features as well as the correlations between 25(OH)D levels in children infected with HP and their ages and degrees of infection.Materials and methodsNinety-four children who underwent upper digestive endoscopy were divided into an HP-positive group without peptic ulcers (Group A), an HP-positive group with peptic ulcers (Group B) and an HP-negative control group (Group C). The serum levels of 25(OH)D and immunoglobulin and the percentages of lymphocyte subsets were determined. HP colonization, the degree of inflammation, and the degree of activity were further evaluated by HE staining and immunohistochemical staining in gastric mucosal biopsy.ResultsThe 25(OH)D level of the HP-positive groups (50.93 ± 16.51 nmol/L) was significantly lower than that of the HP-negative group (62.89 ± 19.18 nmol/L). The 25(OH)D level of Group B (47.79 ± 14.79 nmol/L) was lower than that of Group A (51.53 ± 17.05 nmol/L) and was significantly lower than that of Group C (62.89 ± 19.18 nmol/L). The 25(OH)D level decreased with increasing age, and there was a significant difference between Group C subjects who were ≤5 years old and those who were aged 6–9 years and ≥10 years. The 25(OH)D level was negatively correlated with HP colonization (r = −0.411, P &lt; 0.01) and the degree of inflammation (r = −0.456, P &lt; 0.01). The percentages of lymphocyte subsets and immunoglobulin levels among Groups A, B and C were not significantly different.ConclusionsThe 25(OH)D level was negatively correlated with HP colonization and the degree of inflammation. As the age of the children increased, the level of 25(OH)D decreased, and the susceptibility to HP infection increased

    Superconductivity and Charge-density-wave-like Transition in Th2Cu4As5

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    We report the synthesis, crystal structure, and physical properties of a novel ternary compound, Th2_2Cu4_4As5_5. The material crystallizes in a tetragonal structure with lattice parameters a=4.0716(1)a=4.0716(1) {\AA} and c=24.8131(4)c=24.8131(4) {\AA}. Its structure can be described as an alternating stacking of fluorite-type Th2_2As2_2 layers with antifluorite-type double-layered Cu4_4As3_3 slabs. The measurement of electrical resistivity, magnetic susceptibility and specific heat reveals that Th2_2Cu4_4As5_5 undergoes bulk superconducting transition at 4.2 K. Moreover, all these physical quantities exhibit anomalies at 48 K, where the Hall coefficient change the sign. These findings suggest a charge-density-wave-like (CDW) transition, making Th2_2Cu4_4As5_5 a rare example for studying the interplay between CDW and superconductivity.Comment: 11 pages, 6 figures, and 1 tabl
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