Underground Coal Mine Fingerprint Positioning Based on the MA-VAP Method.

The access points (APs) in a coal mine wireless local area network (WLAN) are generally sparsely distributed. It can, with difficulty, satisfy the basic requirements of the fingerprint positioning based on Wi-Fi. Currently, the effectiveness of positioning is ensured by deploying more APs in an underground tunnel, which significantly increases system cost. This problem can be solved by using the Virtual Access Point (VAP) method that introduces virtual access points (VAPs), which can be virtually arranged in any part of the positioning area without installing actual access points. The drawback of the VAP method is that the generated received signal strength (RSS) value of a VAP is calculated based on the mapping of RSS value from only one corresponding access point (AP). This drawback does not consider the correlation between different AP signals and the generated RSS value of a VAP, which makes the modeling of fingerprint samples and real-time RSS collection incomplete. This study proposed a Multi-Association Virtual Access Point (MA-VAP) method takes into account the influence of multi-association. The multi-association coefficient is calculated based on the correlation between the RSS values of a VAP and multiple access points (APs). Then, the RSS value generated by a VAP is calculated using the multi-association function. The real-time collected RSS values from multiple APs related to this VAP are the input of the multi-association function. The influence of the number of VAPs and their arrangement on positioning accuracy is also analyzed. The experimental positioning results show that the proposed MA-VAP method achieves better positioning performance than the VAP method for the same VAP arrangement. Combined with the Weight K-Nearest Neighbors (WKNN) algorithm and Kernel Principal Component Analysis (KPCA) algorithm, the positioning error of the MA-VAP method of the error distance cumulative distribution function (CDF) at 90% is 4.5 m (with WKNN) and 3.5 m (with KPCA) in the environment with non-line-of-sight (NLOS) interference, and the positioning accuracy is improved by 10% (with WKNN) and 22.2% (with KPCA) compared with the VAP method. The MA-VAP method not only effectively solves the fingerprint positioning problem when APs are sparse deployed, but also improves the positioning accuracy.

Research and Application of Underground WLAN Adaptive Radio Fingerprint Database.

Fingerprint positioning based on WiFi in coal mines has received much attention because of the widespread application of WiFi. Fingerprinting techniques have developed rapidly due to the efforts of many researchers. However, the off-line construction of the radio fingerprint database is a tedious and time-consuming process. When the underground environments change, it may be necessary to update the signal received signal strength indication (RSSI) of all reference points, which will affect the normal working of a personnel positioning system. To solve this problem, an adaptive construction and update method based on a quantum-behaved particle swarm optimization-user-location trajectory feedback (QPSO-ULTF) for a radio fingerprint database is proposed. The principle of ULTF is that the mobile terminal records and uploads the related dataset in the process of user's walking, and it forms the user-location track with RSSI through the analysis and processing of the positioning system server. QPSO algorithm is used for the optimal radio fingerprint match between the RSSI of the access point (AP) contained in the dataset of user-location track and the calibration samples to achieve the adaptive generation and update of the radio fingerprint samples. The experimental results show that the radio fingerprint database generated by the QPSO-ULTF is similar to the traditional radio fingerprint database in the statistical distribution characteristics of the signal received signal strength (RSS) at each reference point. Therefore, the adaptive radio fingerprint database can replace the traditional radio fingerprint database. The comparable results of well-known traditional positioning methods demonstrate that the radio fingerprint database generated or updated by the QPSO-ULTF has a good positioning effect, which can ensure the normal operation of a personnel positioning system.

A Power-Efficient Clustering Protocol for Coal Mine Face Monitoring with Wireless Sensor Networks Under Channel Fading Conditions.

This study proposes a novel power-efficient and anti-fading clustering based on a cross-layer that is specific to the time-varying fading characteristics of channels in the monitoring of coal mine faces with wireless sensor networks. The number of active sensor nodes and a sliding window are set up such that the optimal number of cluster heads (CHs) is selected in each round. Based on a stable expected number of CHs, we explore the channel efficiency between nodes and the base station by using a probe frame and the joint surplus energy in assessing the CH selection. Moreover, the sending power of a node in different periods is regulated by the signal fade margin method. The simulation results demonstrate that compared with several common algorithms, the power-efficient and fading-aware clustering with a cross-layer (PEAFC-CL) protocol features a stable network topology and adaptability under signal time-varying fading, which effectively prolongs the lifetime of the network and reduces network packet loss, thus making it more applicable to the complex and variable environment characteristic of a coal mine face.

An Innovative Model of ISS-Based Multiple Fractures and Gastrointestinal Dysfunction Related to c-Kit Protein Expression on Interstitial Cells of Cajal.

OBJECTIVE: Gastrointestinal dysfunction seriously affects the prognosis and quality of life of patients with multiple fractures. However, experimental evidence of this relationship is lacking. Here we describe a newly developed mouse model of postoperative gastrointestinal dysfunction after multiple fractures. METHODS: Trauma severity was assessed using the injury severity score (ISS). Based on the ISS, a multiple fracture model was established in mice as follows: limb fractures with pelvic fractures and multiple rib fractures; limb fractures with multiple rib fractures; closed fracture of both forelegs with pelvic fracture and rib fractures; closed limb fractures; limb fracture with pelvic fracture; spinal fractures; hind leg fractures with pelvic fractures; pelvic fracture with multiple rib fractures; closed fracture of both fore legs with pelvic fracture; and closed fracture of both fore legs with multiple rib fractures. In each model group, gastrointestinal motility was assayed and the histopathology of the small intestine was examined. Western blot and immunohistochemical analyses of jejunal tissue were performed to detect c-kit protein expression, the level of which was compared with that of a control group. The results of ANOVA are expressed as mean ± standard deviation. RESULTS: In mice with multiple fractures, food intake was greatly reduced, consistent with histopathological evidence of an injured intestinal epithelium. The jejunal tissue of mice in groups a, c, f, and h was characterized by extensively necrotic and exfoliated intestinal mucosal epithelium and inflammatory cell infiltration in the lamina propria. In the gastrointestinal function assay, gastrointestinal motility was significantly reduced in groups a, b, c, f, and g; these group also had a higher ISS (p < 0.01). The expression of c-kit protein in groups with gastrointestinal dysfunction was significantly up-regulated (p < 0.001) compared with the control group. The close correlation between c-kit expression and the ISS indicated an influence of trauma severity on gastrointestinal motility. CONCLUSION: Gastrointestinal dysfunction after multiple fractures was successfully reproduced in a mouse model. In these mice, c-kit expression correlated with gastrointestinal tissue dysfunction and might serve as a therapeutic target.

IE-IQA: Intelligibility Enriched Generalizable No-Reference Image Quality Assessment.

Image quality assessment (IQA) for authentic distortions in the wild is challenging. Though current IQA metrics have achieved decent performance for synthetic distortions, they still cannot be satisfactorily applied to realistic distortions because of the generalization problem. Improving generalization ability is an urgent task to make IQA algorithms serviceable in real-world applications, while relevant research is still rare. Fundamentally, image quality is determined by both distortion degree and intelligibility. However, current IQA metrics mostly focus on the distortion aspect and do not fully investigate the intelligibility, which is crucial for achieving robust quality estimation. Motivated by this, this paper presents a new framework for building highly generalizable image quality model by integrating the intelligibility. We first analyze the relation between intelligibility and image quality. Then we propose a bilateral network to integrate the above two aspects of image quality. During the fusion process, feature selection strategy is further devised to avoid negative transfer. The framework not only catches the conventional distortion features but also integrates intelligibility features properly, based on which a highly generalizable no-reference image quality model is achieved. Extensive experiments are conducted based on five intelligibility tasks, and the results demonstrate that the proposed approach outperforms the state-of-the-art metrics, and the intelligibility task consistently improves metric performance and generalization ability.

Anterior horizontal rafting plate to treat complex osteoporotic tibial plateau fractures: a technical note.

Complex tibial plateau fractures in elderly patients exhibiting severe osteoporosis and articular surface collapse are challenging. Decision-making is difficult when the posterior column is involved. Open reduction and internal fixation of complex tibial plateau fractures in patients with severe osteoporosis are prone to failure. In this paper, we describe a new method for the maintenance of the articular surface of complex tibial plateau fractures in elderly patients. An anterior horizontal rafting plate (3.5-mm-thick reconstruction and locking plate [Zimmer Inc., Warsaw, IN, USA]) is placed via conventional posteromedial and anterolateral incisions. The plate is inserted between the anterior bony surface of the proximal tibia and the subpatellar fat pad; plate positioning is checked under direct vision. The patient is encouraged to begin functional recovery soon after operation. Progressive weight-bearing begins at 10 weeks postoperatively and is gradually increased during fracture healing. Clinical follow-up was performed at 4, 8, and 12 weeks, 6 and 12 months, and yearly thereafter. No articular collapse or fragment displacement was evident on three-dimensional computed tomography performed 6 months after surgery. The knee range of motion was 5-130º at the last follow-up (4 years after surgery). This technique may be a good option for treating complex tibial plateau fractures, especially in elderly patients with severe osteoporosis.

One-step electrochemically synthesized graphene oxide coated on polypyrrole nanowires as anode for microbial fuel cell.

A novel polypyrrole nanowires coated by graphene oxide (PPy-NWs/GO) has been successfully synthesized by one-step electrochemical method, whose structure was different from previously reported PPy/GO composites. The microbial fuel cell equipped with PPy-NWs/GO as anode was fabricated and compared with PPy-NWs ones. The SEM images show that the synthesized PPy-NWs/GO materials possess more surface areas than PPy-NWs. The electrochemical analysis indicated that PPy-NWs/GO anode had lower charge transfer resistance, which may be attributed to synergistic effect of them. The MFC equipped with PPy-NWs/GO anode have higher circle voltages and the power density is about 22.3 mW/m2, which is great higher than that of PPy-NWs about 15.9 mW/m2. These improvements of the MFCs may be due to more bacteria on the larger biofilms based on GO nanosheets, indicating that the PPy-NWs/GO is more effective anode for improving electricity generation.

Human GPR4 and the Notch signaling pathway in endothelial cell tube formation.

G protein-coupled receptor 4 (GPR4) is hypothesized to function as a pH sensor and is important in the regulation of proliferation, migration and angiogenesis of vascular endothelial cells (ECs). Furthermore, the Notch signaling pathway is significant in the regulation of the angiogenic behavior of ECs. However, whether GPR4 regulates angiogenesis via the Notch signaling pathway remains unclear. The present study evaluated the effect of Notch signaling in human GPR4­induced angiogenesis in HMEC­1 cells. The results revealed that GPR4 increased Notch1 expression in a time­dependent manner. In addition, the inhibition of Notch1 expression using small interfering RNA or the Notch receptor inhibitor, γ-secretase inhibitor I, significantly blocked GPR4­induced HMEC­1 tube formation and lymphocyte transendothelial migration. Furthermore, the inhibition of Notch1 blocked GPR4­induced vascular endothelial growth factor and hypoxia-inducible factor 1α expression. Thus, it was demonstrated that GPR4 affects ECs by regulating Notch1, a function that may be important for physiological and pathological angiogenesis.

Epigenetic interventions increase the radiation sensitivity of cancer cells.

Epigenetic changes including DNA methylation, histone modifications, chromatin remodeling and microRNAs play critical roles in tumorigenesis and tumor development. Reversal of epigenetic changes sensitizes some tumor cells to radiation. DNMT-I enhances the response of tumor cells to radiotherapy. AZA demethylated promoters of genes related to ionizing radiation response, such as p16 and hMLH1. The genes expression of the p53, RASSF1, and DAPK gene families was increased by 5-aza-CdR, which induces G2-M phase arrest and increased apoptosis. HDAC-I has both anti-tumor activity and radiation sensitization activity. HDAC-I disrupts both DNA damage sensing and repair processes: HDAC-I disrupts the association between HDAC enzyme and DNA sensor proteins 53BP1 and ATM. HDAC-I changes the acetylation status of both proteins involved in homologous recombination (HR) repair pathway which include BRCA1, Rad51, and Rad50, and proteins involved in non-homologous end joining (NHEJ) repair pathway which include Ku70, and DNA-PK. HDACs are also implicated as essential components in the DNA repair process itself. Besides the radiosensitizing mechanism of intervention of DNA repair, other possible mechanisms including cell cycle redistribution, acetylation of Hsp90, increased apoptosis, and decreased survival signals are also suggested. Some miRNAs also regulate the radiosensitivity of tumor cells. Inhibition of miR-34 expression or function, downregulation of miR-155, upregulation of miR-18a, Overexpression let-7g or knocking down LIN28B, and ectopically overexpressed miR-10 in cells with low endogenous miR-101 level increase the response of cells to irradiation. For radiation-resistant cancer cells, miR-7 sensitizes the radiation for cells which activated EGFR-PI3K-AKT signaling pathway.

RNAi targeting GPR4 influences HMEC-1 gene expression by microarray analysis.

G-protein coupled receptor 4 (GPR4) belongs to a protein family comprised of 3 closely related G protein-coupled receptors. Recent studies have shown that GPR4 plays important roles in angiogenesis, proton sensing, and regulating tumor cells as an oncogenic gene. How GPR4 conducts its functions? Rare has been known. In order to detect the genes related to GPR4, microarray technology was employed. GPR4 is highly expressed in human vascular endothelial cell HMEC-1. Small interfering RNA against GPR4 was used to knockdown GPR4 expression in HMEC-1. Then RNA from the GPR4 knockdown cells and control cells were analyzed through genome microarray. Microarray results shown that among the whole genes and expressed sequence tags, 447 differentially expressed genes were identified, containing 318 up-regulated genes and 129 down-regulated genes. These genes whose expression dramatically changed may be involved in the GPR4 functions. These genes were related to cell apoptosis, cytoskeleton and signal transduction, cell proliferation, differentiation and cell-cycle regulation, gene transcription and translation and cell material and energy metabolism.

Relations between GPR4 expression, microvascular density (MVD) and clinical pathological characteristics of patients with epithelial ovarian carcinoma (EOC).

G-protein coupled receptor 4 (GPR4) is a G protein-coupled receptor (GPCR) activated by sphingosylphosphorylcholine (SPC) and lysophosphatidylcholine (LPC). Later studies indicated that GPR4 can serve as a proton sensor. GPR4 has been known to play a critical role in the tube formation of vascular endothelial cells, and GPR4 overexpression is observed in various types of malignancies, suggesting its involvement in the cancer-related angiogenesis. In this study, we examined the GPR4 expression levels in blood vessels of ovarian cancer, and analyzed the relationship between GPR4 expression and the clinical and pathological characteristics of patients with epithelial ovarian carcinomas (EOC). Results from immunohistochemistry showed that GPR4 is detectable in the endothelium of vessels of both EOC and benign ovarian tumor tissue, but the expression levels were significantly increased in EOC. Moreover the increased expression is accompanied by a higher microvascular density (MVD) in EOC compared to that in the benign ovarian tumors. We demonstrated a positive correlation between GPR4 expression density and MVD in EOC, but not benign ovarian tumor tissues. Further analyses indicated that GPR4 expression and MVD in EOC were correlated to the status of lymph node metastasis and clinical stage, but not significantly correlated to the pathological classifications, histopathological grades, the amounts of ascites, status of peritoneal cytology, tumor sizes, or patients' ages. These results suggested that GPR4 may play an important role in the development of EOC, and its overexpression might be required for the angiogenesis, tumor growth, and metastasis of EOC.

HDAC as a therapeutic target for treatment of endometrial cancers.

Accumulating evidence suggested that epigenetic changes such as promoter-specific DNA hypermethylation and histone deacetylation cause tumor suppressor gene silencing and contribute to malignant transformation. Treatment of cancer cells with HDAC inhibitors can reactivate the expression of silenced genes, block the cell cycle, and induce cell apoptosis. In vitro experiments in cancer cell cultures and in vivo studies using mouse xynograft model have shown that HDAC inhibitors deliver potent anti-cancer effects. Clinical trials have led to approval of SAHA (Vorinostat) for treatment of lymphoma. Endometrial cancer (EC) is the most frequent malignancy in women's reproductive tract. EC is known for extensive epigenetic alterations, including overexpression of HDAC and DNMT enzymes, and the frequent epigenetic silencing of DNA repair genes such as MLH1, tumor suppressor genes PTEN, and progesterone receptor, which suggests a potentially high sensitivity of this type of cancer to HDAC inhibitors. Indeed, studies from many laboratories using various models have shown that HDAC inhibitors are promising chemotherapy reagents for endometrial cancers. This review summarizes the results from these studies, with an emphasis to provide an update on the new findings from new drugs. Background information on HDAC expression in EC, and features of HDAC inhibitors are presented based on their relevance to our focused topic. The combined application of HDAC inhibitors with radiation therapy and other conventional therapeutic reagents are also discussed.