Search Results

1 - 6 of 6 items

  • Author: Li-Na Wang x
Clear All Modify Search
Experimental and Mathematical Investigations on Unconfined Compressive Behaviour of Costal Soft Soil under Complicated Freezing Processes

Abstract

In order to properly understand the effect of freezing-thawing circle (FTC) to mechanical behavior of costal soft soil (CSS), unconfined compressive test is conducted. Six kind FTC times are designed from zero to five. The tested data show that: (1) unconfined compressive strength of CCS decreases nonlinearly with more FTC, and the strength after five FTC times becomes about 22% of its original strength without any freezing-thawing experience; (2) stress-strain curves of all unconfined compressive samples can be well fitted by three-parameter hyperbolic model; (3) and relationship between two parameters and FTC times can be fitted by exponent function, while another parameter can be considered as 0.95. Consequently, one composite hyperbolic- exponent empirical formula is established in order to describe freezing-thawing-dependent stress-strain behavior of CSS. Finally, good agreements have been found between tested data and simulated results.

Open access
Factors Associated with Death Due to 2009 Influenza A (H1N1) Virus Infection and Acute Respiratory Distress Syndrome in Beijing, 2009 - 2011

Abstract

Objective Patients with H1N1 virus infection were hospitalized and quarantined, and some of them developed into acute respiratory failure, and were transfered to the medical intensive care unit of Beijing Ditan Hospital, Capital Medical University in Beijing, China.

Methods The clinical features and preliminary epidemiologic findings among 30 patients with confirmed H1N1 virus infection who developed into acute respiratory failure for ventilatory support were investigated.

Results A total of 30 patients (37.43 ± 18.80 years old) with 2009 influenza A (H1N1) related acute respiratory distress syndrome (ARDS) received treatment with mechanical ventilation, 15 cases of whom were male and 17 cases died of ARDS. Fatal cases were significantly associated with an APACHE Ⅱ score (P = 0.016), but not with PaO2/FIO2 (P = 0.912) and chest radiograph (P = 0.333). The most common complication was acute renal failure (n = 9). Five patients received extracorporeal membrane oxygenation (ECMO), 3 of whom died and the others survived. The major causes of death were multiple organ dysfunction syndrome (MODS) (39%), intractable respiratory failure (27%) and sepsis (20%).

Conclusions Most patients with respiratory failure due to influenza A (H1N1) virus infection were young, with a high mortality, particularly associated with APACHE ∥ score, secondary infection of lung or type 2 diabetes mellitus.

Open access
NPS2390, a selective calcium-sensing receptor antagonist controls the phenotypic modulation of hypoxic human pulmonary arterial smooth muscle cells by regulating autophagy

Abstract

Background and Objectives

Calcium-sensing receptor (CaSR) is known to regulate hypoxia-induced pulmonary hypertension (HPH) and vascular remodeling via the phenotypic modulation of pulmonary arterial smooth muscle cells (PASMCs) in small pulmonary arteries. Moreover, autophagy is an essential modulator of VSMC phenotype. But it is not clear whether CaSR can regulate autophagy involving the phenotypic modulation under hypoxia.

Methods

The viability of human PASMCs was detected by cell cycle and BrdU. The expressions of proliferation protein, phenotypic marker protein, and autophagy protein in human PASMCs were determined by western blot.

Results

Our results showed that hypoxia-induced autophagy was considerable at 24 h. The addition of NPS2390 decreased the expression of autophagy protein and synthetic phenotype marker protein osteopontin and increased the expression of contractile phenotype marker protein SMA-ɑ and calponin via suppressing downstream PI3K/Akt/mTOR signal pathways.

Conclusions

Our study demonstrates that treatment of NPS2390 was conducive to inhibit the proliferation and reverse phenotypic modulation of PASMCs by regulating autophagy levels.

Open access
Development and evaluation of orally disintegrating tablets containing the mosapride resin complex

Abstract

The purpose of this study was to prepare a mosapride citrate-resin (Amberlite® IRP 88) complex and orally fast-disintegrating tablets of the resin complex. The resinate complex of mosapride-Amberlite® IRP 88, mass ratio 2:1, was prepared in an ethanol-water solution. The effects of alcohol concentration, temperature, and pH of the solution on complex formation were evaluated. The complex physicochemical properties were characterized by differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. Orally disintegrating tablets were prepared by direct compression and were optimized using the response surface method. Optimized orally fast-disintegrating tablets disintegrated within 18 s. The pH dependence of mosapride release from the tablet decreased drug dissolution in simulated saliva, whereas it promptly released in the pH 1.0 solution. The data reported herein clearly demonstrate that tablets containing the mosapride-Amberlite® IRP 88 complex for oral disintegration could be particularly useful for patients with swallowing difficulties.

Open access
Effects of Electroacupuncture at Neiguan Acupoint on SOD and Mitochondrial Transmembrane Potential of Rabbits with Myocardial Ischemia-Reperfusion Injury

Abstract

Objective: To investigate the influence of electroacupuncture (EA) preconditioning at Nei Guan point (PC6) on the opening of mitochondrial permeability transition pore (MPTP) of rabbits with myocardial ischemia-reperrfusion injury, and its underlying mechanism that protects myocardium from injury.

Methods: 18 New Zealand rabbits were randomly assigned to pseudo-operation, model and EA groups, 6 in each group. Setting up models by ligation of coronary artery and electrically stimulating the rabbits in EA group 20 min per day in 5 days before modeling. Testing the activity of serum SOD with the method of actinochemistry, testing changes of mitochondrial transmembrane potential of myocardial cells with the method of synchronous spectrometry, using spectrophotometry to test the changes of the absorption of mitochondria at the spectrum of 520nm to check the opening of MPTP, and testing the apotosis of cells by means of terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL).

Results: Compared with model groups, the SOD activity of myocardial cells was significantly enhanced, and the apotosis index (AI) was reduced(P<0.01),mitochondrial transmembrane potential was significantly increased (P<0.05),absorption of mitochondria was significantly decreased(P<0.01).

Conclusion: EA can remarkably improve myocardial ischemia - reperfusion injury, and protect myocardium.

Open access
Xylazine regulates the release of glycine and aspartic acid in rat brain

Abstract

Introduction

Xylazine, a type of α2-adrenoceptors, is a commonly used drug in veterinary medicine. Xylazine-induced changes in the content of amino acid neurotransmitters – glycine (Gly) and aspartic acid (Asp), in different brain regions and neurons were studied.

Material and Methods

Wistar rats were administered 50 mg/kg or 70 mg/kg of xylazine by intraperitoneal injection. In addition, in vitro experiments were conducted, in which neurons were treated with 15 μg/mL, 25 μg/mL, 35μg/mL, and 45 μg/mL of xylazine. Test methods were based on the enzyme-linked immunosorbent assays (ELISA).

Results

During anaesthesia, Asp levels in each brain area were significantly lower compared to the control group. Except for the cerebrum, levels of Gly in other brain areas were significantly increased during the anaesthesia period. In vitro, xylazine-related neuron secretion of Gly increased significantly compared to the control group at 60 min and 90 min. Moreover, xylazine caused a significant decrease in the levels of Asp secreted by neurons at 20 min, but gradually returned to the level of the control group.

Conclusion

The data showed that during anaesthesia the overall levels of Asp decreased and overall levels of Gly increased. In addition, the inhibitory effect of xylazine on Asp and the promotion of Gly were dose-dependent. Our data showed that different effects of xylazine on excitatory and inhibitory neurotransmitters provided a theoretical basis for the mechanism of xylazine activity in clinical anaesthesia.

Open access