Pharmacokinetic, bioequivalence, and safety assessments of two brands of 30-mg nifedipine controlled-release formulations in Chinese healthy subjects.

Objective: This study aimed to analyze the pharmacokinetic (PK) characteristics, safety, and bioequivalence (BE) of a test (T) preparation of a nifedipine controlled-release tablet and the reference (R) drug (Adalat GTIS) in Chinese study participants in the context of fasting and postprandial states.

Materials And Methods: An open-label, single-center, randomized, single-dose, two-period study was designed including two separate arms, one with administration under fasting conditions and one with administration under postprandial conditions (high-fat, high-calorie breakfast). After oral administration, the nifedipine concentrations in plasma were quantitatively analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) at regular intervals.

Simultaneous determination of maltol and maltol glucuronide in human plasma and urine by HPLC-MS/MS: Application in clinical study in patients with iron deficiency.

Ferric maltol has been used as an oral drug for iron deficiency. This study developed and fully validated the novel HPLC-MS/MS methods to determine maltol and maltol glucuronide simultaneously in plasma and urine. The protein precipitation was performed by addition of acetonitrile in the plasma samples.

Seismic performance analysis of shallow-buried large-scale three-box-section segment-connected pipeline structure under multiple actions.

To ensure the safety operation of inter-basin water transfer project, it is important to understand the seismic performance of shallow-buried large-scale segment-connected pipeline structure under earthquake and other multiple actions. In this paper, a 3D FE model is built in details for the seismic assessment of large-scale prestressed concrete inverted-siphon shallow-buried under riverbed, and a method is proposed to realize multiple interactions of the viscoelastic boundary elements to finite elements, the compressible fluid to structure and the sealed joints made of rubber belt between adjacent segments. The inverted-siphon is longitudinally composited by 58 segments in total length of 858.

Case Study on Prestressed CFRP Plates Applied for Strengthening Hollow-Section Beam Removed from an Old Bridge.

With the wide application of carbon fiber reinforced polymer (CFRP) plate, used for strengthening existed concrete structures, the prestressing technology of CFRP plate is becoming a hot topic, in order to sufficiently develop its high-strength peculiarity. In this paper, a full-scale hollow-section beam with length of 16 m taken from an old bridge which was in service for about 20 years was first examined for existed cracks and repaired by filling epoxy adhesive, and then the beam was strengthened with prestressed CFRP plates. The CFRP plates were tensioned and fixed with flat-plate anchorages at ends and bonded with adhesive on the bottom surface of the beam.

Bond Behavior of Steel Bars in Concrete Confined with Stirrups under Freeze-Thaw Cycles.

In order to evaluate the influence of freeze-thaw action on the durability of concrete structures, this paper presented an experimental study to investigate the effects of freezing-thawing cycles and concrete strength on the bond behavior between steel bars and concrete confined with stirrups. Through freeze-thaw cycles and center pullout tests, the failure mode of pullout specimen, concrete strength, mass loss, dynamic elastic modulus, and bond-slip curves were analyzed. At last, the bond-slip constitutive model was proposed for specimens with stirrup confinement under freeze-thaw action.

Bond Behaviors of Steel Fiber in Mortar Affected by Inclination Angle and Fiber Spacing.

Considering the random orientation and distribution of steel fibers in concrete, the synergistic reinforcement of steel fibers on concrete is much complex than the bond of single fiber. It is meaningful to study the bond behavior of steel fiber during many actions. With the inclination angle of steel fiber to pullout direction and the fiber spacing as main factors, this paper carried out fifteen groups of pullout tests for hook-end steel fiber embedded in manufactured sand mortar.

Investigating the Mechanical Property and Enhanced Mechanism of Modified Pisha Sandstone Geopolymer via Ion Exchange Solidification.

The Yellow River has the highest sediment concentration in the world, and the Yellow River coarse sediment mainly comes from a particular kind of argillaceous sandstone, Pisha sandstone. This paper reports an investigation of the possibility of development of low-cost engineering materials using Pisha sandstone via ion exchange modification. The effect of modifiers with different concentration on the inhibition of volume expansion and the strength enhancement of modified Pisha sandstone were studied via ion exchange solidification.

Experimental Study on Chloride Ion Diffusion in Concrete Affected by Exposure Conditions.

The transport mechanism of chloride ions in concrete is relatively complicated since the erosion process is influenced by many factors. To investigate the effect of exposure conditions on the chloride ion diffusion property, three exposure conditions (long-term immersion in static sodium chloride solution, long-term immersion in circulating sodium chloride solution and dry-wet cycles in circulating sodium chloride solution) were considered in chloride ion diffusion experiments. Experimental results indicated that the chloride ion content at a certain depth increased with erosion age.

Influence of Particle Morphology of Ground Fly Ash on the Fluidity and Strength of Cement Paste.

The grinding process has become widely used to improve the fineness and performance of fly ash. However, most studies focus on the particle size distribution of ground fly ash, while the particle morphology is also an important factor to affect the performance of cement paste. This article aims at three different kinds of ground fly ash from the ball mill and vertical mill, and the particle morphology is observed by scanning electron microscopy (SEM) to calculate the spherical destruction (the ratio of spherical particles broken into irregular particles in the grinding process of fly ash), which provides a quantification of the morphology change in the grinding process.

Development and validation of samples stabilization strategy and LC-MS/MS method for simultaneous determination of clevidipine and its primary metabolite in human plasma: Application to clinical pharmacokinetic study in Chinese healthy volunteers.

A feasible LC-MS/MS method with reliable stabilizers consisted of sodium fluoride, ascorbic acid and formic acid was developed and validated for the determination of clevidipine and its primary metabolite (H152/81) in human plasma. Sodium fluoride existing in the vacutainer tubes was used to inhibit esterase activity to protect the clevidipine from hydrolysis as soon as blood was collected. Ascorbic acid and formic acid were added to the separated plasma samples to avoid the oxidation and further hydrolysis of clevidipine and H152/81.

A simplified and reliable LC-tandem mass spectrometry method for determination of ulipristal acetate in human plasma and its application to a pharmacokinetic study in healthy Chinese volunteers.

In this study, a simplified, sensitive and reliable LC-tandem mass spectrometry method was established and validated for the quantification of ulipristal acetate (UPA) in human plasma and for the investigation of pharmacokinetic profile of UPA following a single oral administration of ella (UPA 30-mg tablet) in healthy Chinese volunteers. Plasma samples were analyzed after being processed by protein precipitation with methanol. Chromatographic separation was performed on a Kinetex EVO C column (2.

LC-APCI-MS/MS assay for quantitation of ethyl esters of eicosapentaenoic acid and docosahexaenoic acid in human plasma and its application in a pharmacokinetic study.

A simple and specific LC-MS/MS method was developed and validated for the determination of ethyl ester of eicosapentaenoic acid (EPAEE) and ethyl ester of docosahexaenoic acid (DHAEE). After deproteinized with acetonitrile, the plasma samples were separated on a C18 column using a gradient elution system consisted of methanol and 1.0 mM ammonium acetate in water.

Two high-performance liquid chromatography-tandem mass spectrometry methods for determination of edaravone and taurine in human plasma: Application to drug-drug interaction and pharmacokinetic studies.

Two high-performance liquid chromatography-tandem mass spectrometry methods were developed and validated for the quantification of edaravone (method A) or taurine (method B) in human plasma. After protein precipitation, separations were achieved on an Ultimate XB-C8 (2.1 × 50 mm, 3.

Shrinkage and Mechanical Properties of Self-Compacting SFRC With Calcium-Sulfoaluminate Expansive Agent.

With the premise of ensuring workability on a fresh mixture, the volume stability of hardened self-compacting steel fiber reinforced concrete (SFRC) becomes an issue due to the content of cementitious materials increased with the volume fraction of steel fiber. By using the expansive agent to reduce the shrinkage deformation of self-compacting SFRC, the strength reduction of hardened self-compacting SFRC is another issue. To solve these issues, this paper performed an experimental investigation on the workability, shrinkage, and mechanical properties of self-compacting SFRC compared to the self-compacting concrete (SCC) with or without an expansive agent.

Bond Properties of Steel Bar in Concrete under Water Environment.

The present study concerns the bond behavior of steel bar in concrete under a water environment. This topic was put forward because of the changes of concrete under a water environment and the importance of reliable anchorage of steel bar for reinforced concrete structures. Thirty bond specimens with deformed steel bars were immersed in water and experimentally studied by pull-out tests.

Behavior of Rectangular-Sectional Steel Tubular Columns Filled with High-Strength Steel Fiber Reinforced Concrete Under Axial Compression.

This paper studies the effect of high-strength steel fiber reinforced concrete (SFRC) on the axial compression behavior of rectangular-sectional SFRC-filled steel tube columns. The purpose is to improve the integrated bearing capacity of these composite columns. Nine rectangular-sectional SFRC-filled steel tube columns and one normal concrete-filled steel tube column were designed and tested under axial loading to failure.

Testing and Prediction of the Strength Development of Recycled-Aggregate Concrete with Large Particle Natural Aggregate.

In this paper, a new recycled aggregate concrete (RAC) was produced with composite coarse aggregate and fine recycled aggregate. The composite coarse aggregate was mixed into continuous gradation by large particle natural aggregate with small particle recycled aggregate. To explore the time-dependent developments of the compressive strength and splitting tensile strength of this new RAC, 320 groups of cubic specimens were tested at different curing ages from 3 days to 360 days to measure the compressive and splitting tensile strengths.

Experimental Investigation on Columns of Steel Fiber Reinforced Concrete with Recycled Aggregates under Large Eccentric Compression Load.

To improve the structural application of steel fiber-reinforced concrete with recycled aggregates (SFRC-RA) composited in gradation by large-particle natural coarse aggregate and small-particle recycled coarse aggregate, the large eccentric compression behavior of eight SFRC-RA columns was experimentally investigated in this paper. The main parameters considered were the strength of the SFRC-RA and the volume fraction of the steel fiber. Details about the sectional concrete strain, the longitudinal steel bar strain, the lateral displacement, the cracking load, the crack distribution and crack width, and the ultimate load of the SFRC-RA columns were measured.

Pharmacokinetics and safety of salbutamol/ambroxol fixed-dose combination granules in healthy Chinese subjects .

Objectives: The aim of the study was to investigate the pharmacokinetics and tolerability of salbutamol/ambroxol fixed-dose combination granules following single and multiple dosing in healthy Chinese subjects.

Materials And Methods: This was a randomized, open-label, two-period, one-sequence study (n = 12). Each subject received a single oral dose in period 1 and multiple doses in period 2.

Simultaneous determination of acetaminophen and oxycodone in human plasma by LC-MS/MS and its application to a pharmacokinetic study.

A simple and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of acetaminophen and oxycodone in human plasma. Acetaminophen-d4 and oxycodone-d3 were used as internal standards. The challenge encountered in the method development that the high plasma concentration level of acetaminophen made the MS response saturated while the desired lower limit of quantification (LLOQ) for oxycodone was hard to reach was well solved.

Investigation of a potential drug-drug interaction between salbutamol and ambroxol and bioequivalence of a new fixed-dose combination containing these two drugs in healthy Chinese subjects.

Objectives: The aims of the study were to investigate the potential drug-drug interaction between salbutamol and ambroxol, the bioequivalence of the new fixed-dose combination containing salbutamol and ambroxol compared with co-administration of the two separate formulations, and to describe the safety and tolerability of the fixed-dose combination formulation in healthy Chinese volunteers.

Materials And Methods: An open-label, single-dose, four-treatment, four-period crossover study for evaluation of drug-drug interaction and bioequivalence (n = 24) was performed. Each participant received salbutamol 4 mg, ambroxol 15 mg, salbutamol 4 mg co-administered with ambroxol 15 mg or fixed-dose combination formulation (salbutamol 4 mg and ambroxol 15 mg).

Dataset of tensile strength development of concrete with manufactured sand.

This article presents 755 groups splitting tensile strength tests data of concrete with manufactured sand (MSC) in different curing age ranged from 1 day to 388 days related to the research article "Experimental study on tensile strength development of concrete with manufactured sand" (Zhao et al., 2017) [1]. These data were used to evaluate the precision of the prediction formulas of tensile strength of MSC, and can be applied as dataset for further studies.