1,153 research outputs found
Integrated WiFi/PDR/Smartphone using an unscented Kalman filter algorithm for 3D indoor localization
Because of the high calculation cost and poor performance of a traditional planar map when dealing with complicated indoor geographic information, a WiFi fingerprint indoor positioning system cannot be widely employed on a smartphone platform. By making full use of the hardware sensors embedded in the smartphone, this study proposes an integrated approach to a three-dimensional (3D) indoor positioning system. First, an improved K-means clustering method is adopted to reduce the fingerprint database retrieval time and enhance positioning efficiency. Next, with the mobile phone’s acceleration sensor, a new step counting method based on auto-correlation analysis is proposed to achieve cell phone inertial navigation positioning. Furthermore, the integration of WiFi positioning with Pedestrian Dead Reckoning (PDR) obtains higher positional accuracy with the help of the Unscented Kalman Filter algorithm. Finally, a hybrid 3D positioning system based on Unity 3D, which can carry out real-time positioning for targets in 3D scenes, is designed for the fluent operation of mobile terminals
Antidiabetic effect and mode of action of cytopiloyne
Cytopiloyne was identified as a novel polyacetylenic compound. However, its antidiabetic properties are poorly understood. The aim of the present study was to investigate the anti-diabetic effect and mode of action of cytopiloyne on type 2 diabetes (T2D). We first evaluated the therapeutic effect of cytopiloyne on T2D in db/db mice. We found that one dose of cytopiloyne reduced postprandial glucose levels while increasing blood insulin levels. Accordingly, long-term treatment with cytopiloyne reduced postprandial blood glucose levels, increased blood insulin, improved glucose tolerance, suppressed the level of glycosylated hemoglobin A1c (HbA1c), and protected pancreatic islets in db/db mice. Next, we studied the anti-diabetic mechanism of action of cytopiloyne. We showed that cytopiloyne failed to decrease blood glucose in streptozocin- (STZ-)treated mice whose β cells were already destroyed. Additionally, cytopiloyne dose dependently increased insulin secretion and expression in β cells. The increase of insulin secretion/expression of cytopiloyne was regulated by protein kinase C α (PKC α ) and its activators, calcium, and diacylglycerol (DAG). Overall, our data suggest that cytopiloyne treats T2D via regulation of insulin production involving the calcium/DAG/PKC α cascade in β cells. These data thus identify the molecular mechanism of action of cytopiloyne and prove its therapeutic potential in T2D
Recent Progress on C-4-Modified Podophyllotoxin Analogs as Potent Antitumor Agents: C-4-MODIFIED PODOPHYLLOTOXIN ANALOGS
Podophyllotoxin (PPT), as well as its congeners and derivatives, exhibits pronounced biological activities, especially antineoplastic effects. Its strong inhibitory effect on tumor cell growth led to the development of three of the most highly prescribed anticancer drugs in the world, etoposide, teniposide, and the water-soluble prodrug etoposide phosphate. Their clinical success as well as intriguing mechanism of action stimulated great interest in further modification of PPT for better antitumor activity. The C-4 position has been a major target for structural derivatization aimed at either producing more potent compounds or overcoming drug resistance. Accordingly, numerous PPT derivatives have been prepared via hemisynthesis and important structure–activity relationship (SAR) correlations have been identified. Several resulting compounds, including GL-331, TOP-53, and NK611, reached clinical trials. Some excellent reviews on the distribution, sources, applications, synthesis, and SAR of PPT have been published. This review focuses on a second generation of new etoposide-related drugs and provides detailed coverage of the current status and recent development of C-4-modified PPT analogs as anticancer clinical trial candidates
Synthesis, biological evaluation, and physicochemical property assessment of 4-substituted 2-phenylaminoquinazolines as Mer tyrosine kinase inhibitors
Current results identified 4-substituted 2-phenylaminoquinazoline compounds as novel Mer tyrosine kinase (Mer TK) inhibitors with a new scaffold. Twenty-one 2,4-disubstituted quinazolines (series 4-7) were designed, synthesized, and evaluated against Mer TK and a panel of human tumor cell lines aimed at exploring new Mer TK inhibitors as novel potential antitumor agents. A new lead, 4b, was discovered with a good balance between high potency (IC50 0.68ÎĽM) in the Mer TK assay and antiproliferative activity against MV4-11 (GI50 8.54ÎĽM), as well as other human tumor cell lines (GI50<20ÎĽM), and a desirable druglike property profile with low logP value (2.54) and high aqueous solubility (95.6ÎĽg/mL). Molecular modeling elucidated an expected binding mode of 4b with Mer TK and necessary interactions between them, thus supporting the hypothesis that Mer TK might be a biologic target of this kind of new active compound
Synthesis of novel spin-labeled derivatives of 5-FU as potential antineoplastic agents
Chemotherapy is a general treatment option for various cancers, including lung cancer. In order to find compounds with superior bioactivity and less toxicity against lung cancer, novel spin-labeled 5-fluorouracil (5-FU) derivatives (3a–f) were synthesized and evaluated against four human tumor cell lines (A-549, DU-145, KB, and KBvin). Two promising compounds 3d and 3f exhibited IC50 values of 2.76 and 2.38 μM, respectively, against non-small cell lung carcinoma cell line A-549. These compounds were twofold more cytotoxic than 5-FU and less toxic against other tested cell lines. Compound 3f exhibited seven times more selective cytotoxicity against A-549 than 5-FU. Our results suggest that compounds 3d and 3f merit further investigation for development into clinical trial candidates for non-small cell lung cancer
Design, synthesis, and mechanism of action of 2-(3-hydroxy-5-methoxyphenyl)-6-pyrrolidinylquinolin-4-one as a potent anticancer lead
New 6- (or 6,7-) substituted 2-(hydroxyl substituted phenyl)quinolin-4-one derivatives were synthesized and screened for antiproliferative effects against cancer cell lines. Structure-activity relationship correlations were established and the most promising compound 2-(3-hydroxy-5-methoxyphenyl)-6-pyrrolidin-1-ylquinolin-4-one (6h) exhibited strong inhibitory activity against various human cancer cell lines, particularly non-small cell lung cancer NCI-H522. Additional studies suggested a mechanism of action resembling that of the antimitotic drug vincristine. The presence of a C-ring OH group in 6h will allow this compound to be converted readily to a water soluble and physiochemically stable hydrophilic prodrug. Compound 6h is proposed as a new anticancer lead compound
A competing-risk-based score for predicting twenty-year risk of incident diabetes: the Beijing Longitudinal Study of Ageing study
Few risk tools have been proposed to quantify the long-term risk of diabetes among middle-aged and elderly individuals in China. The present study aimed to develop a risk tool to estimate the 20-year risk of developing diabetes while incorporating competing risks. A three-stage stratification random-clustering sampling procedure was conducted to ensure the representativeness of the Beijing elderly. We prospectively followed 1857 community residents aged 55 years and above who were free of diabetes at baseline examination. Sub-distribution hazards models were used to adjust for the competing risks of non-diabetes death. The cumulative incidence function of twenty-year diabetes event rates was 11.60% after adjusting for the competing risks of non-diabetes death. Age, body mass index, fasting plasma glucose, health status, and physical activity were selected to form the score. The area under the ROC curve (AUC) was 0.76 (95% Confidence Interval: 0.72–0.80), and the optimism-corrected AUC was 0.78 (95% Confidence Interval: 0.69–0.87) after internal validation by bootstrapping. The calibration plot showed that the actual diabetes risk was similar to the predicted risk. The cut-off value of the risk score was 19 points, marking mark the difference between low-risk and high-risk patients, which exhibited a sensitivity of 0.74 and specificity of 0.65
REG3A overexpression functions as a negative predictive and prognostic biomarker in rectal cancer patients receiving CCRT
Background. Concurrent chemoradiotherapy (CCRT) is suggested before resection surgery in the control of rectal cancer. Unfortunately, treatment outcomes are widely variable and highly patientspecific. Notably, rectal cancer patients with distant metastasis generally have a much lower survival rate. Accordingly, a better understanding of the genetic background of patient cohorts can aid in predicting CCRT efficacy and clinical outcomes for rectal cancer before distant metastasis. Methods. A published transcriptome dataset (GSE35452) (n=46) was utilized to distinguish prospective genes concerning the response to CCRT. We recruited 172 rectal cancer patients, and the samples were collected during surgical resection after CCRT. Immunohistochemical (IHC) staining was performed to evaluate the expression level of regenerating family member 3 alpha (REG3A). Pearson's chi-squared test appraised the relevance of REG3A protein expression to clinicopathological parameters. The Kaplan-Meier method was utilized to generate survival curves, and the log-rank test was performed to compare the survival distributions between two given groups. Results. Employing a transcriptome dataset (GSE35452) and focusing on the inflammatory response (GO: 0006954), we recognized that REG3A is the most significantly upregulated gene among CCRT nonresponders (log2 ratio=1.2472, p=0.0079). Following IHC validation, high immunoexpression of REG3A was considerably linked to advanced post-CCRT tumor status (p<0.001), post-CCRT lymph node metastasis (p=0.042), vascular invasion (p=0.028), and low-grade tumor regression (p=0.009). In the multivariate analysis, high immunoexpression of REG3A was independently correlated with poor disease-specific survival (DSS) (p=0.004) and metastasis-free survival (MeFS) (p=0.045). The results of the bioinformatic analysis also supported the idea that REG3A overexpression is implicated in rectal carcinogenesis. Conclusion. In the current study, we demonstrated that REG3A overexpression is correlated with poor CCRT effectiveness and inferior patient survival in rectal cancer. The predictive and prognostic utility of REG3A expression may direct patient stratification and decisionmaking more accurately for those patients
Synergistic synthesis of quasi-monocrystal CdS nanoboxes with high-energy facets
Hollow nanostructures with a highly oriented lattice structure and active facets are promising for catalytic applications, while their preparation via traditional approaches contains multiple steps and is time and energy consuming. Here, we demonstrate a new one-step strategy involving two complementary reactions which promote each other; it is capable of producing unique hollow nanoparticles. Specifically, we apply synergic cooperation of cation exchange and chemical etching to attack PbS nanosized cubes (NCs) and produce CdS quasi-monocrystal nanoboxes (QMNBs) which possess the smallest dimensions reported so far, a metastable zinc-blende phase, a large specific surface area, and particularly high-energy {100} facets directly visualized by aberration-corrected scanning transmission electron microscopy. These properties in combination allow the nanoboxes to acquire exceptional photocatalytic activities. As an extension of the approach, we use the same strategy to prepare Co9S8 and Cu7.2S4 single-crystal hollow nanooctahedrons (SCHNOs) successfully. Hence, the synergic reaction synthesis strategy exhibits great potential in engineering unique nanostructures with superior properties
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