Study on coupling effect of soil structure and overconsolidation on mechanical properties of loess.

Soil structure and overconsolidation are two important factors that affect soil strength. Current research studies have primarily focused on the influence of single factors, and relatively few studies have studied the coupling effect of the two. In this paper, the effects of structure and overconsolidation on the mechanical properties of loess under certain conditions have been studied by compression tests and direct shear tests. Undisturbed loess, remolded loess, overconsolidated undisturbed loess, and overconsolidated remolded loess were investigated in this work. The results indicate that structure and overconsolidation can enhance the overall strength of the soil, but the effects of these two factors also interfere and weaken each other. The combined effect of structure and overconsolidation can lead to higher soil shear strength. Compared with remolded normally consolidated soil, when the vertical pressure is 50kPa, 100kPa, and 200kPa, the structure increases the strength of the original normally consolidated soil by 35%, 21%, and 7%, respectively. Overconsolidation increases the strength of the remolded overconsolidated soil by 51.3%, 40.9%, and 17.7%, respectively. The combined effect of structure and overconsolidation increases the strength of the original overconsolidated soil by 89%, 72.5%, and 32.7%, respectively. The increase in soil strength caused by the coupling effect is smaller than the sum of the strength increase caused by the two factors. The main reason is that the soil structure can reduces the compaction effect of overconsolidation, and the compaction load applied during the process of overconsolidation can also damage the soil structure, and the scanning electron microscopy observation is consistent with the experimental results and analysis. Finally, an empirical relation was developed for the effect of overconsolidation, structural properties, and their coupling on soil strength. The calculated results of the formula are highly consistent with the experimental data, and have good rationality and accuracy.

Effects of HMGA2 on the biological characteristics and stemness acquisition of gastric cancer cells.

BACKGROUND AND STUDY AIMS: The high mobility group A2 (HMGA2), a nonhistone nuclear binding protein, modulates transcription by altering the chromatin architecture of the target gene DNA in its specific AT-hooks region. HMGA2 overexpression has been observed in embryonic tissue and many malignant neoplasms. This study sought to verify whether HMGA2 plays a role in the biological functions of gastric cancer cells, such as cell proliferation, invasiveness, migration, and stem cell acquisition, and to provide some ideas for further research on the metastatic mechanism of gastric cancer. PATIENTS AND METHODS: HMGA2's effects on the proliferation, invasiveness, and migration capabilities of gastric cancer cells were individually detected by BrdU, Transwell, and wound healing assays. Western blotting and immunofluorescence were used to evaluate whether HMGA2 could promote the acquisition of gastric cancer cells. Biostatistical analyses were performed using SPSS 17.0 for Windows. RESULTS: HMGA2 expression levels in gastric cancer cell lines were significantly higher than those in human immortalized gastric epithelial cell lines (p < 0.01). Gastric cancer cell proliferation was inhibited when HMGA2 was overexpressed (p < 0.05). The invasiveness and migration capabilities of gastric cancer cells with HMGA2 overexpression were enhanced more than those of the corresponding control groups (p < 0.05). HMGA2 overexpression promotes the stemness acquisition of stem cells from gastric cancer cells. CONCLUSIONS: This study verified that the HMGA2 structural transcription factor promotes invasiveness, migration, and acquisition of gastric cancer cells. Furthermore, our findings provide significant insight for further research on the metastatic mechanism of gastric cancer.

An integrated high-flux cold atomic beam source for strontium.

We present the design, construction, and characterization of an integrated cold atomic beam source for strontium (Sr), which is based on a compact Zeeman slower for slowing the thermal atomic beam and an atomic deflector for selecting the cold flux. By adopting arrays of permanent magnets to produce the magnetic fields of the slower and the deflector, we effectively reduce the system size and power compared to traditional systems with magnetic coils. After the slower cooling, one can employ additional transverse cooling in the radial direction and improve the atom collimation. The atomic deflectors employ two stages of two-dimensional magnetic-optical trapping (MOT) to deflect the cold flux, whose atomic speed is lower than 50 m/s, by 20° from the thermal atomic beam. We characterize the cold atomic beam flux of the source by measuring the loading rate of a three-dimensional MOT. The loading rates reach up to 109 atoms/s. The setup is compact, highly tunable, lightweight, and requires low electrical power, which addresses the challenge of reducing the complexity of building optical atomic clocks and quantum simulation devices based on Sr.

Robot location privacy protection based on Q-learning particle swarm optimization algorithm in mobile crowdsensing.

In the recent years, with the rapid development of science and technology, robot location-based service (RLBS) has become the main application service on mobile intelligent devices. When people use location services, it generates a large amount of location data with real location information. If a malicious third party gets this location information, it will cause the risk of location-related privacy disclosure for users. The wide application of crowdsensing service has brought about the leakage of personal privacy. However, the existing privacy protection strategies cannot adapt to the crowdsensing environment. In this paper, we propose a novel location privacy protection based on the Q-learning particle swarm optimization algorithm in mobile crowdsensing. By generalizing tasks, this new algorithm makes the attacker unable to distinguish the specific tasks completed by users, cuts off the association between users and tasks, and protects users' location privacy. The strategy uses Q-learning to continuously combine different confounding tasks and train a confounding task scheme that can output the lowest rejection rate. The Q-learning method is improved by particle swarm optimization algorithm, which improves the optimization ability of the method. Experimental results show that this scheme has good performance in privacy budget error, availability, and cloud timeliness and greatly improves the security of user location data. In terms of inhibition ratio, the value is close to the optimal value.

PEA prevented early BBB disruption after cerebral ischaemic/reperfusion (I/R) injury through regulation of ROCK/MLC signaling.

Palmitoylethanolamide (PEA) offers a strong protection against BBB disruption and neurological deficits after cerebral ischaemic/reperfusion (I/R) injury. To date, these BBB protective effects of PEA are mainly attributed to PPARα-mediated actions. However, whether PEA protects against BBB disruption through direct regulation of cytoskeletal microfilaments remains unknown. Here, we identified PEA as a Rho-associated protein kinase (ROCK2) inhibitor (IC50 = 38.4 ± 4.8 µM). In vitro data suggested that PEA reduced the activation of ROCK/MLC signaling and stress fiber formation within microvascular endothelial cells (ECs) after oxygen-glucose deprivation (OGD), and consequently attenuated early (0-4 h) EC barrier disruption. These actions of PEA could not be blocked by the PPARα antagonist GW6471. In summary, the present study described a previously unexplored role of PEA as a ROCK2 inhibitor, and propose a PPARα-independent mechanism for pharmacological effects of PEA.

Effect of conglomeration gradation on loess shear strength with different water content.

Particle gradation and water content are important factors affecting shear strength of soil. However, due to chemical cementation and molecular attraction, loess particles commonly stick together forming conglomerations. Till date, the superposition effect of water content and conglomeration gradation on loess shear strength has rarely been studied and undeniably requires further systematic explorations and development. In this study, loess samples were prepared with three conglomeration gradations and five water contents, and the direct shear tests were systematically performed. The shear strength of sample 1 (continuous conglomeration gradation) was found to be the best, followed by sample 2 (large size conglomerations), and sample 3 (small size conglomerations). The difference of samples' shear strength decreased with increasing water content, and almost closed to zero when water content was 20%. The cohesion of samples first increased and then decreased with increasing water content, the maximum cohesion occurred at 10% water content. The internal friction angles decreased with increasing water content, and reached similar minimum values when the water content was 15%. The increased percentage values of cohesion and internal friction angle caused by conglomeration gradation are in the range of 33.2%-42.1% and 9.8%-32.5%, respectively. Finally, the empirical formulas for water content-cohesion and water content-internal friction angle of different conglomeration gradations samples were established, and the calculated values are in good agreement with test data. The effect of loess conglomeration gradation on shear strength decreased with increasing water content. When the water content was less than 15%, using a good conglomeration graduation could effectively improve loss shear strength.

HMGA2 regulates epithelial-mesenchymal transition and the acquisition of tumor stem cell properties through TWIST1 in gastric cancer.

High expression of high mobility group protein A2 (HMGA2) is correlated with the invasiveness of gastric cancer and is an independent prognostic factor. The reason may be that HMGA2 promotes epithelial-mesenchymal transition (EMT) and the acquisition of tumor stem cell properties, yet the mechanism remains unclear. In this study, immunohistochemistry and western blot analysis revealed that the expression of HMGA2 and Twist-related protein 1 (TWIST1) in gastric carcinoma tissues was higher than that in the peritumoral tissues and that the expression levels of these two proteins were positively correlated. The protein expression levels of HMGA2 and TWIST1 were high in the poorly differentiated gastric cancer MKN-45 cells and were low in the moderately differentiated SGC-7901 cells. TWIST1 was inhibited after HMGA2 interference and was significantly increased after overexpression of HMGA2. Luciferase experiments showed that TWIST1 was a direct downstream target gene of HMGA2. The simultaneous interference of HMGA2 expression and the overexpression of TWIST1 in MKN-45 cells reversed the inhibitory effect of HMGA2 interference on the invasion and migration of gastric cancer cells, EMT and the expression of stemness markers. However, the simultaneous overexpression of HMGA2 and the interference of TWIST1 expression in the SGC-7901 cells reversed the promoter effect of HMGA2 overexpression on the invasiveness and migration of gastric cancer cells, EMT and the expression of stemness markers. In addition, animal experiments showed that TWIST1 overexpression reversed the inhibition of HMGA2 interference on the metastasis of MKN-45 cells. Therefore, HMGA2 regulates the EMT of gastric cancer cells and the acquisition of tumor stem cell properties through direct regulation of the downstream target gene TWIST1.

Mutated K-ras activates CDK8 to stimulate the epithelial-to-mesenchymal transition in pancreatic cancer in part via the Wnt/ß-catenin signaling pathway.

Cyclin-dependent kinase 8 (CDK8), a gene encoding the cyclin-dependent kinase (CDK) component of the Mediator complex, is known as a colon cancer oncogene. Our recent study showed that CDK8 plays an important role in the formation of pancreatic cancer, but the CDK8 expression levels were not completely identical in different pancreatic cancer samples. The level of CDK8 expression depended on whether the K-ras gene was mutated; its expression was much higher in samples carrying a K-ras mutation than in wild-type K-ras samples. Moreover, CDK8 expression was reduced following mutated K-ras knockdown in K-ras-mutated pancreatic cancer cells, whereas CDK8 expression was increased following expression of mutated K-ras in wild-type K-ras cells. Our study demonstrates that mutated K-ras stimulates CDK8 expression, possibly by regulating HIF-1α, and both CDK8 and mutated K-ras were confirmed to promote cell proliferation and prevent apoptosis in vitro. Additionally, we found that both CDK8 and mutated K-ras promote the invasion and migration of pancreatic cancer cells via the positive regulation of the Wnt/ß-catenin signaling pathway, thereby increasing the expression of Snail1 and ZEB1, which act as important stimulating factors of the epithelial-to-mesenchymal transition (EMT). Finally, knockdown of either CDK8 or mutated K-ras contributed to attenuated pancreatic cancer growth in BALB/c nude mice. In conclusion, these findings demonstrate that mutated K-ras promotes CDK8 expression and that the regulatory effects of CDK8 on the EMT are partially attributed to the Wnt/ß-catenin signaling pathway.

Coexpression of HMGA2 and Oct4 predicts an unfavorable prognosis in human gastric cancer.

High mobility group protein A2 (HMGA2) and octamer-binding transcription factor 4 (Oct4) are transcription factors that play major roles in the acquisition of cancer stemness phenotypes and tumorigenicity of malignant neoplasms. The aim of this study was to analyze the association between HMGA2 and Oct4 expression and various clinicopathologic features in gastric cancer patients including invasion, metastasis, and clinical prognosis, in addition to overall survival. Immunohistochemistry was performed to explore the expression of HMGA2 and Oct4 in 158 gastric cancer and surrounding non-tumor tissues. Moreover, HMGA2 and Oct4 mRNA and protein levels were also detected by qRT-PCR and Western blotting, respectively, in 86 clinical tissue specimens and various gastric epithelial cell lines (GES-1, SGC7901, MKN45, and MKN27). Finally, associations between HMGA2 and Oct4 expression and clinicopathological features were analyzed by Pearson correlation coefficient. Survival analysis was performed by univariate and multivariate analyses. Taken together, we found that HMGA2 and Oct4 expression was significantly higher in gastric cancer tissues compared with non-cancerous tissues (P < 0.01), and HMGA2 and Oct4 protein levels were significantly higher in poorly differentiated gastric cancer cell lines (MKN45), moderately differentiated cell lines (SGC7901), and well-differentiated cell lines (MKN28) compared with human immortalized gastric epithelial cell lines (GES-1) (P < 0.01). Elevated HMGA2 and Oct4 levels were significantly associated with poor clinical prognosis (P < 0.05). Further conclusion showed that coexpression of HMGA2 and Oct4 in gastric cancer correlated with tumor invasion, metastasis, and clinical prognosis and predicted an unfavorable clinical outcome. These transcription factors may represent useful biomarkers to identify patients at high risk of postoperative recurrence.

MicroRNA­21 inhibits SMAD7 expression through a target sequence in the 3' untranslated region and inhibits proliferation of renal tubular epithelial cells.

MicroRNAs (miRNAs) are a class of small non­coding single­stranded RNAs that regulate gene expression at the posttranscriptional level. Since the identification of miRNA, accumulating research has shown their involvement in numerous biological processes, including timing of developmental patterning, embryogenesis, cell differentiation, organogenesis, growth control and pathogenesis of human diseases. It is estimated that >30% human genes may be regulated by miRNA, and that each miRNA can regulate >100 target mRNAs. The widespread and distinct expression pattern of miRNAs in normal and disease states has been extensively investigated in the context of human diseases. Due to the diversity of targets, it is challenging to identify the specific target genes and elucidate the biological function of a certain miRNAs. In the present study, it was confirmed that SMAD7 is a direct target of miR­21, and overexpression of miR­21 may inhibit the proliferation of rat renal tubular epithelial cells. These findings confirm the results of previous studies, which have demonstrated that miR­21 regulates the expression of SMAD7 protein. However, further investigation is required to determine whether miR­21 is involved in renal development and disease, particularly diabetic nephropathy.

[Clinical significance of D-dimer activity in thrombosis of patients with return of spontaneous circulation after cardiopulmonary resuscitation].

OBJECTIVE: To investigate the clinical significance of D-dimer contents in peripheral blood for monitoring the efficacy of thrombolytic therapy in patients with return of spontaneous circulation (ROSC) of cardiopulmonary resuscitation (CPR) cardiopulmonary resuscitation after cardiac arrest. METHODS: Forty-seven patients with sudden cardiac arrest received CPR according to 2005 American Heart Association (AHA) guidelines for CPR and emergency cardiovascular care (ECC). At the early stage of ROSC, those patients underwent head and breast CT scan if they were in a state of unconsciousness and had unstable vital signs. If intracranial hemorrhage, dissection of aorta and pneumothorax were rule out, and those patients who maintained blood circulation for over 24 hours were included. The expression of D-dimer contents in peripheral blood was determined at 0, 1, 2, 4, 8, 12 h after CPR in all patients. And the patients were randomly divided into control and experiment groups. Prior to thrombolysis, the patients whose D-dimer more than 512 µg/L were classified as Group A (n = 17); those whose D-dimer below 512 µg/L Group B (n = 14); and the remaining control group whose family members refused thrombolytic therapy Group C (n = 16). The general data, Glasgow coma scale, survival rate and the change of D-dimer in peripheral blood were analyzed. RESULTS: In Group A, D-dimer level began to increase significantly at CPR 1 hour. It peaked at CPR 2 hours then decreased gradually. The final survival rate was 67%. The survival rate and GCS were higher than those of Groups B and C. In Group B, the D-dimer concentrations began to increase gradually at CPR1 hour, peaked at CPR 12 hours and then decreased. The survival rate and GCS was lower than those of Group A and similar to those of Group C. Group C was control group with no thrombolysis. CONCLUSION: For those ROSC patients with D-dimer concentrations significantly higher than usual, the pathogenesis of cardiac arrest may be concerned with thromboembolism, thrombosis in circulatory system and hyperviscosity. After an initiation of thrombolytic therapy, blocked blood vessels are recanalized, blood circulation improves and the cause of cardiac arrest is removed. Thus their survival rate becomes better. For those with D-dimer concentrations no higher than usual, the cause of cardiac arrest is not concerned with thromboembolism, thrombolytic therapy can not improve the patient outcome. And the final survival rate remains unchanged. The significance of thrombolytic therapy is none.

[Identification and diagnosis of myocardial damage and acute myocardial infarction during cardiopulmonary resuscitation].

OBJECTIVE: To observe the change in contents of creatine kinase isoenzyme MB (CK-MB) and cardiac troponin I (cTnI) in peripheral blood, the elevation of ST in electrocardiogram, and the result of coronary arteriography, to identify myocardial damage and acute myocardial infarction during cardiopulmonary resuscitation (CPR). METHODS: Twenty-six patients with sudden cardiac arrest received CPR, and those patients who had blood circulation maintained for over 24 hours were included. The expression of CK-MB and cTnI activation in peripheral blood were determined at 0, 4, 8, 12, 16 and 20 hours after CPR in all patients. Electrocardiogram was checked every 2 hours in all patients. If CK-MB, cTnI and ST segment of electrocardiogram was higher than usual, or myocardial infarct with suspicious elevation of ST (STEMI), coronary arteriography and interventional therapy were carried out immediately. Patients were divided into three groups. The patients who were not found to have coronary artery block were classified as group A (15 cases), those who were found to have coronary artery block were group B (6 cases), and the remaining patients in whom ST segment of electrocardiogram did not elevate, and coronary arteriography and interventional therapy were not consider were classified as group C (5 cases). Control group consisted of 15 healthy people (group D). The change in CK-MB and cTnI in peripheral blood and the elevation of electrocardiogram ST segment were analyzed. RESULTS: In group A, CK-MB level began to elevate at CPR 4 hours, and it peaked at CPR 12 hours. cTnI began to raise at CPR 4 hours, peaking at CPR 16 hours, then decreased gradually. Elevation of ST was seen in more than two leads in electrocardiogram at the beginning of restoration of spontaneous circulation (ROSC), then lowered quickly, and the decrease exceeded 50% of the elevation at ROSC 2 hours. In group B, the levels of CK-MB and cTnI began to increase at CPR 4 hours, and remained elevated at CPR 20 hours. ST segment was elevated in more than two leads in electrocardiogram at the beginning of ROSC, and remained elevated after ROSC 2 hours. In group C, the CK-MB and cTnI concentrations were increased 4 hours after successful CPR, and reached peak at CPR 12, 16 hours respectively, then they decreased. ST segment of electrocardiogram was not elevated. In group D, the CK-MB and cTnI concentration was in the normal range. ST segment of electrocardiogram was not elevated. CONCLUSION: All patients manifested myocardial damage after CPR. Some patients showed STEMI after CPR. CK-MB and cTnI concentrations increased gradually after successful CPR without specificity for earlier identification of myocardial damage and STEMI. It is necessary to find a new reliable marker to check for myocardial damage. Relatively speaking, elevation of the ST segment in electrocardiogram has more predictive value. A decrease exceeds 50% of the elevation of ST segment in electrocardiogram at ROSC 2 hours, or the peak of contents of CK-MB and cTnI appear at CPR 12 hours or 16 hours indicates myocardial damage. If the elevation of ST segment does not descend after ROSC 2 hours, or the levels of CK-MB and cTnI remain elevated at CPR 20 hours, STEMI should be suspected, and it is necessary to undertake interventional therapy or thrombolysis therapy.

Role of sterol regulatory element binding proteins in the regulation of Galpha(i2) expression in cultured atrial cells.

We have previously demonstrated that growth of embryonic chick atrial cells in medium supplemented with lipoprotein-depleted serum (LPDS) resulted in a coordinate increase in the expression of genes involved in the parasympathetic response of the heart (the M2 muscarinic receptor; the alpha-subunit of the heterotrimeric G protein, Galpha(i2); and the inward rectifying K+ channel protein, GIRK1) and a marked increase in the negative chronotropic response of atrial cells to muscarinic stimulation. In the present study, we demonstrate that regulation of Galpha(i2) promoter activity by LPDS is mediated by the binding of a sterol regulatory element binding protein (SREBP) to a sterol regulatory element (SRE) in the Galpha(i2) promoter. Deletion and point mutation of this putative SRE interfered with the regulation of the Galpha(i2) promoter by SREBP and LPDS. Furthermore gel shift assays demonstrated that point mutations in the putative Galpha(i2) SRE markedly inhibited the binding of purified SREBP to oligonucleotides containing the Galpha(i2) SRE sequence. The expression of a dominant-negative SREBP mutant interfered with LPDS stimulation of Galpha(i2) promoter activity. Finally, we demonstrate that SREBP-1 is markedly more potent than SREBP-2 for the stimulation of Galpha(i2) promoter activity, suggesting that SREBP1 may play a role in the regulation of Galpha(i2) expression. These are the first data to demonstrate SREBP regulation of a protein not involved in lipid homeostasis and suggest a new relationship between lipid metabolism and the parasympathetic response of the heart.

3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors interfere with angiogenesis by inhibiting the geranylgeranylation of RhoA.

Angiogenesis is implicated in the pathogenesis of cancer, rheumatoid arthritis, and atherosclerosis and in the treatment of coronary artery and peripheral vascular disease. Here, cholesterol-lowering agents, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, are shown to interfere with angiogenesis. In vivo, the HMG-CoA reductase inhibitor simvastatin dose-dependently inhibited capillary growth in both vascular endothelial growth factor-stimulated chick chorioallantoic membranes and basic fibroblast growth factor-stimulated mouse corneas. In vitro, the development of tubelike structures by human microvascular endothelial cells cultured on 3D collagen gels was inhibited at simvastatin concentrations similar to those found in the serum of patients on therapeutic doses of this agent. HMG-CoA reductase inhibitors interfered with angiogenesis via inhibition of the geranylgeranylation and membrane localization of RhoA. Simvastatin inhibited membrane localization of RhoA with a concentration dependence similar to that for the inhibition of tube formation, whereas geranylgeranyl pyrophosphate, the substrate for the geranylgeranylation of Rho, reversed the effect of simvastatin on tube formation and on the membrane localization of RhoA. Furthermore, tube formation was inhibited by GGTI, a specific inhibitor of the geranylgeranylation of Rho; by C3 exotoxin, which inactivates Rho; and by the adenoviral expression of a dominant-negative RhoA mutant. The expression of a dominant-activating RhoA mutant reversed the effect of simvastatin on tube formation. Finally, HMG-CoA reductase inhibitors inhibited signaling by vascular endothelial growth factor, Akt, and focal adhesion kinase, three RhoA-dependent pathways known to be involved in angiogenesis. This study demonstrates a new relationship between lipid metabolism and angiogenesis and an antiangiogenic effect of HMG-CoA reductase inhibitors with possible important therapeutic implications.