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Hyperglycemia aggravates cerebral ischemia/reperfusion (I/R) injury via vascular injury. There is still a lack of effective pharmaceutical preparations for cerebral I/R injury under hyperglycemia. This study aimed to investigate the effects of oxymatrine (OMT) on hyperglycemia-exacerbated cerebral I/R injury in vitro and in vivo. The middle cerebral artery occlusion (MCAO) and reperfusion was established in the rats under hyperglycemia. Meanwhile, oxygen–glucose deprivation and reoxygenation (OGD/R) with high glucose was used as an in vitro model of hyperglycemic cerebral I/R injury. The results showed that the neurological deficit score, mortality, infarct volume and penumbra apoptosis in hyperglycemia group were significantly higher than those in normal glucose group. OMT pre-treated obviously reduced the degree of neurological deficit, mortality, infarct volume, improve cerebral blood flow after I/R in rats with hyperglycemia, and increase the survival rate of human brain microvascular endothelial cells (HBMECs) in high glucose and OGD/R group. OMT significantly improved the ultrastructure changes of endothelial cells, and maintain the migration and angiogenesis potency of HBMECs in high glucose and OGD/R group. OMT obviously alleviated the down-regulating CD31 and CD105 expression in cerebral microvessels caused by hyperglycemia. It is concluded that OMT treatment might alleviate cerebral I/R injury under hyperglycemia via protecting microvessels. [ABSTRACT FROM AUTHOR]

Dry sliding wear tests were performed for 7075 Al alloy under a load of 25–250 N at 25–200 °C. The wear behaviors and mechanisms under various testing conditions were explored. A mild-to-severe wear transition is noticed to occur with an increase in the load at 25–200 °C. With the temperature increasing, the wear loss decreases constantly under the low load of less than 50 N. It can be suggested that the 7075 Al alloy presents a high wear resistance under a high ambient temperature and low load. Its high wear resistance is found to be attributed to the existence of mechanically mixing layer (MML). The predominant wear mechanism is adhesive and abrasive wear at room temperature. With the ambient temperature and load increasing, oxidative wear and plastic extrusive wear successively prevail due to thermal oxidation and softening of matrix. [ABSTRACT FROM AUTHOR]

Mitochondrial uncoupling protein 2 (UCP2) deficiency exacerbates brain damage following cerebral ischemia/reperfusion (I/R). The Nod-like receptor protein-3 (NLRP3) inflammasome also plays a vital role in cerebral I/R damage. However, the effect of UCP2 on NLRP3 inflammasome-mediated hyperglycemia and I/R damage is not clear. In the present study, UCP2-knockout (UCP2−/−) and wild-type (WT) mice were used to establish a model of middle cerebral artery occlusion (MCAO) and reperfusion under normo- and hyperglycemic conditions. HT22 cells were established as a model of oxygen–glucose deprivation and reoxygenation (OGD/R) with high glucose to mimic hyperglycemia and I/R in vitro. HT22 cells were treated with/without different concentrations of the UCP2-specific inhibitor genipin for different periods of time. The results showed that UCP2 deficiency significantly increased histopathological changes and apoptosis after cerebral I/R damage in hyperglycemic mice. Moreover, UCP2 deficiency enhanced NLRP3 inflammasome activation in neurons when cerebral I/R damage was exacerbated by hyperglycemia. Furthermore, UCP2 deficiency enhanced NLRP3 inflammasome activation and reactive oxygen species (ROS) production in HT22 cells under OGD/R and high-glucose conditions. UCP2 deficiency aggravated hyperglycemia-induced exacerbation of cerebral I/R damage. UCP2 deficiency also enhanced NLRP3 inflammasome activation and ROS production in neurons in vitro and in vivo. These findings suggest that UCP2 deficiency enhances NLRP3 inflammasome activation following hyperglycemia-induced exacerbation of cerebral I/R damage in vitro and in vivo. UCP2 may be a potential therapeutic target for hyperglycemia-induced exacerbation of cerebral I/R damage. [ABSTRACT FROM AUTHOR]

Background: When the risk of lymph node metastasis (LNM) is considered minimal in patients with early gastric cancer (EGC), endoscopic submucosal dissection (ESD) is an effective alternative to radical resection. This study aims to estimate the feasibility of ESD for EGC with ulceration. Patients and Methods: We retrospectively reviewed data from 691 patients who underwent gastrectomy for EGC with ulceration. Subsequently, a stratification system for lesions was created based on the expanded ESD criteria, and the associations between the subgroups and the rate of LNM were analyzed. Results: LNM was confirmed in 16.5% (114/691) of patients. Univariate analysis demonstrated that age, sex, tumor size, macroscopic features, depth of invasion, tumor differentiation, Lauren type, lymphovascular invasion (LVI), and perineural invasion were associated with LNM. Multivariate analysis showed that LVI [odds ratio (OR) = 16.761, P < 0.001], SM1 invasion (OR = 2.159, P = 0.028), and SM2 invasion (OR = 3.230, P < 0.001) were independent risk factors for LNM. LNM occurred in undifferentiated mucosal tumors, with ulceration being 1.7% (2/116) when the lesion was smaller than 20 mm. Further stratification revealed that among lesions < 30 mm in size, undifferentiated tumors with SM1 invasion had a higher rate of LNM and a lower disease-free survival rate than differentiated tumors with SM1 invasion and tumors limited to the mucosal layer. Conclusions: Depth of invasion and LVI were strongly associated with LNM in ulcerative EGC. Endoscopic resection may be applicable for undifferentiated mucosal ulcerative EGC < 30 mm in size, and additional investigation is needed to evaluate its safety. [ABSTRACT FROM AUTHOR]

Recently, microRNA-498 (miR-498) plays important effect in human cancers. Nonetheless, the role of miR-498 is still unclear in gastric cancer (GC). Therefore, this study was designed to investigate the function of miR-498 in GC tissues and cell lines (SGC-7901, BGC-823, MGC-803). The expressions of miR-498 and BMI-1 were examined in GC tissues via the RT-qPCR assay. The function of miR-498 was investigated through MTT and transwell assays. The relationship between miR-498 and BMI-1 was testified by dual luciferase assay. The protein expression of EMT markers, AKT pathway markers and BMI-1 was measured through western blot. The expression of miR-498 was decreased in GC tissues which predicted poor prognosis of GC patients. Moreover, functional analyses show that the overexpression of miR-498 inhibited the progression of GC. Furthermore, BMI-1 was a direct target of miR-498 which was upregulated in GC. Especially, the upregulation of BMI-1 recovered the suppressive effect of miR-498 in GC. In addition, miR-498 inhibited the metastasis and proliferation of GC cells through blocking EMT and AKT pathway. MiR-498, by targeting BMI-1, presents a plethora of tumor suppressor activities in GC cells. [ABSTRACT FROM AUTHOR]

Aims: Previous studies indicated that urinary glucose (UG) had a limited efficacy in diabetes screening. This study was designed to have a re-evaluation of its efficacy, taking into consideration the collection method of urine and the measurement approach for UG among Chinese adults.Methods: This cross-sectional study enrolled a total of 7689 participants without known diabetes, who were fasted and asked to empty bladders before a 75 g glucose loading. Urine was collected 2 h post glucose loading, and UG was measured using quantitative and qualitative approaches. The efficacy of UG in detecting diabetes was assessed by the receiver operating characteristic (ROC) curve.Results: The area under the ROC curve was 0.89 for quantitative UG and 0.87 for qualitative UG. Quantitative UG was positively correlated with fasting plasma glucose (FPG) and 2 h plasma glucose (2 h PG) (r = 0.55 and 0.56, respectively, both P < 0.001). Quantitative UG displayed a sensitivity of 82.9% and a specificity of 84.7% in detecting diabetes at the corresponding optimal cutoff of 130 mg. Qualitative UG exhibited a sensitivity of 80.2% and a specificity of 85.6% at the optimal cutoff of glycosuria + 1. In addition, the sensitivity of both quantitative and qualitative UG was significantly higher than that of HbA1c (≥ 6.5%) (P < 0.001) and had a comparable sensitivity to 2 h PG (≥ 11.1 mmol/L) (P = 0.493).Conclusions: UG, either quantitatively or qualitatively measured at 2 h post glucose loading, was effective in diabetes screening. This indicates that UG is a feasible approach for diabetes screening. [ABSTRACT FROM AUTHOR]

Composites of nominal composition (PbTe)1−x(CoTe)x (x = 0-0.18) were fabricated by high pressure (6 GPa) sintering (773 K) method. The thermoelectric performances were investigated in the temperature range of 293-773 K. The experimental results show that CoTe utilized as the secondary phase can remarkably enhance the TE properties of PbTe, of which the highest ZT value reaches 0.88 at 473 K when x = 0.14. The enhancement of TE performance owes much to its high electric conductivity of CoTe. Meanwhile, the high pressure sintering (HPS) samples consist of nanoparticle, which significantly enhances the boundary scattering on carriers, decreases thermal conductivity, and increases Seebeck coefficient. All the results indicate that HPS method and the addition of CoTe-composite are effective methods to enhance the thermoelectric performance of PbTe as a potential TE material. [ABSTRACT FROM AUTHOR]

In this paper, powder metallurgy technology combined with high-pressure sintering (HPS) were used to fabricate MnTe ( x = −0.02, 0, 0.04) alloys at 743 K. The products of synthesis were identified by x-ray diffraction; microstructures were examined by field-emission scanning electron microscopy (FE-SEM); the electrical conductivity and the Seebeck coefficient were measured in the temperature range of 300-800 K. The results show that all HPS samples consisted of nanoparticles. MnTe ( x = −0.02, 0, 0.04) thermoelectric materials with a high Seebeck coefficient and low electrical conductivity have potential to warrant further study in the future. The peak figure of the merit, ZT, reaches 0.59 for MnTe at 773 K. [ABSTRACT FROM AUTHOR]

With the improvements in modern radar resolution, the Gaussian-fluctuation model based on the central limit theorem does not accurately describe the scattering echo from targets. In contrast, the heavytailed Rayleigh distribution, based on the generalized central limit theorem, performs well in modeling the synthetic aperture radar (SAR) images, whereas its application to multi-look image processing is difficult. We describe successful modeling of multilook polarimetric SAR images with the heavy-tailed Rayleigh distribution and present novel parameter estimators based on matrix log-cumulants for the heavy-tailed Rayleigh distribution including the equivalent number of looks (ENL). First, a compound variable of heavy-tailed Rayleigh distribution is divided into a product of a positive alpha-stable variable and a complex Gaussian variable. The parameter estimations of the characteristic exponent and scale parameter based on log-cumulants in a single polarization channel are then derived. Second, the matrix log-cumulants (MLCs) for full polarization in multilook images are obtained, which can be applied to estimate model parameters. Therefore, a novel ENL estimator based on MLC is presented that describes the model more precisely. Extended to all other multivariable product models, this estimator performs better than existing methods. Finally, calculations on both simulated and real data are performed that give good fits with theoretical results. Multilook processing in one image with a fixed pixel number can improve parameter estimations over single-look processing. Our heavy-tailed Rayleigh model with its parameter estimation provides a new method to analyze the multilook polarimetric SAR images for target detection and classification. [ABSTRACT FROM AUTHOR]

primary challenge of agent-based policy learning in complex and uncertain environments is escalating computational complexity with the size of the task space (action choices and world states) and the number of agents. Nonetheless, there is ample evidence in the natural world that high-functioning social mammals learn to solve complex problems with ease, both individually and cooperatively. This ability to solve computationally intractable problems stems from both brain circuits for hierarchical representation of state and action spaces and learned policies as well as constraints imposed by social cognition. Using biologically derived mechanisms for state representation and mammalian social intelligence, we constrain state-action choices in reinforcement learning in order to improve learning efficiency. Analysis results bound the reduction in computational complexity due to state abstraction, hierarchical representation, and socially constrained action selection in agent-based learning problems that can be described as variants of Markov decision processes. Investigation of two task domains, single-robot herding and multirobot foraging, shows that theoretical bounds hold and that acceptable policies emerge, which reduce task completion time, computational cost, and/or memory resources compared to learning without hierarchical representations and with no social knowledge. [ABSTRACT FROM AUTHOR]

Aim: To gain insight into the histopathological responses and molecular targets in the inhibition of growth of human gastric cancer treated with celecoxib (a cyclooxygenase [COX]-2 inhibitor) combined with octreotide. Methods: Seventy five patients with gastric cancer undergoing curative gastrectomy or extended resection were randomly divided into 3 groups. The apoptosis of tumor cells was measured by terminal deoxynucleotide transferase-mediated dUTP nick end-labeling (TUNEL) assay. Gastric cancer microvessel density (MVD) and the expression of COX-2 were evaluated by immunohistochemical staining. The expression of somatostatin receptor (SSTR)-2 was detected with the biomolecular interaction analysis system. The transcription of non-steroidal anti-inflammatory drug-activated gene (NAG)-1 was measured by RT-PCR. Results: Compared with the control and celecoxib groups, more necrosis in the combination group was observed. The apoptotic rate in the combination group (7.06%±0.67%) was significantly higher than that in the control group (6.23%±1.29%, P<0.05). The MVD decreased considerably in the combination group. The upregulation of NAG-1 was displayed both in the celecoxib and combination groups. The positive rate of SSTR-2 in gastric cancers treated with celecoxib (48%) was significantly higher than that of control group (12%) after surgery ( P<0.05). Conclusion: Celecoxib combined with octreotide significantly promoted necrosis in gastric adenocarci-noma through the induction of apoptosis and the reduction of MVD. NAG-1 and SSTR-2 might be the molecular targets for celecoxib or octreotide. [ABSTRACT FROM AUTHOR]

To probe the scale inhibition mechanisms, calcium carbonate scale occurring before and after the addition of scale inhibitors was collected. The results from scale SEM confirm that, without scale inhibitor, calcium carbonate scale shows rhombohedron and hexagon, which are the characteristic feathers of calcite. After addition of inhibitors, morphology of scale is changed, and the more efficient the scale inhibitor is, the more greatly the morphology is modified. To elucidate the scale constitute, they were further analyzed by FT-IR, XRD. Besides calcite, vaterite and aragonite occur in calcium carbonate scale after addition of inhibitors, and the higher scale inhibition efficiency is, the more vaterite presents in scale. It can be concluded that the alteration of morphology is ascribed to the change of crystal form. There are three stages in the crystallizing process including occurrence and disappearing of unstable phase, occurrence and disappearing of metastable phase, development of stable phase. Without scale inhibitors, metastable phases usually transform into stable phase, thus the main constitute of formed scale is calcite. When scale inhibitors are added, both formation and transformation of metastable phases are inhibited, which results in the occurrence of aragonite and vaterite. From the fact that more vaterite presents in scale with a more efficient scale inhibitor added, we can see that the function of scale inhibitor is realized mainly by controlling the crystallizing process at the second stage. [ABSTRACT FROM AUTHOR]

Many superionic mixed ionic-electronic conductors with a liquid-like sublattice have been identified as high efficiency thermoelectric materials, but their applications are limited due to the possibility of decomposition when subjected to high electronic currents and large temperature gradients. Here, through systematically investigating electromigration in copper sulfide/selenide thermoelectric materials, we reveal the mechanism for atom migration and deposition based on a critical chemical potential difference. Then, a strategy for stable use is proposed: constructing a series of electronically conducting, but ion-blocking barriers to reset the chemical potential of such conductors to keep it below the threshold for decomposition, even if it is used with high electric currents and/or large temperature differences. This strategy not only opens the possibility of using such conductors in thermoelectric applications, but may also provide approaches to engineer perovskite photovoltaic materials and the experimental methods may be applicable to understanding dendrite growth in lithium ion batteries. Mixed ionic-electronic conductors are limited by material decomposition. Here the authors reveal the mechanism for atom migration and deposition in Cu2-δ(S,Se) materials based on a critical chemical potential difference and propose electronically conducting, ion-blocking interfaces to enhance stability. [ABSTRACT FROM AUTHOR]