Computer Simulation of PAN/PVP Blends Compatibility and Preparation of Aligned PAN Porous Nanofibers via Magnetic-Field-Assisted Electrospinning PAN/PVP Blends

Binary blend compatibility of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) was computationally simulated at both molecular and mesoscopic levels in order to provide theoretical support for preparing PAN porous nanofibers from PAN/PVP blends. In molecular simulation, Flory-Huggins interaction parameters were calculated to estimate the blend compatibility, in which PAN and PVP were found to be immiscible. This had been further validated by the mesoscopic simulation in terms of the free energy density，the order parameters, and the mesoscopic morphology. Aligned PAN porous nanofibers were prepared by selectively removing PVP from the PAN/PVP blend nanofibers which was prepared by Magnetic-field-assisted electrospinning (MFAES).</p

Local gene delivery via endovascular stents coated with dodecylated chitosan–plasmid DNA nanoparticles

Development of efficacious therapeutic strategies to prevent and inhibit the occurrences of restenosis after percutaneous transluminal coronary angioplasty is critical for the treatment of cardiovascular diseases. In this study, the feasibility and efficiency of stents coated with dodecylated chitosan–plasmid DNA nanoparticles (DCDNPs) were evaluated as scaffolds for localized and prolonged delivery of reporter genes into the diseased blood vessel wall. Dodecylated chitosan–plasmid DNA complexes formed stable positive charged nanospheres with mean diameter of approximately 90–180 nm and zeta potential of +28 ± 3 mV. As prepared DCDNPs were spray-coated on stents, a thin layer of dense DCDNPs was successfully distributed onto the metal struts of the endovascular stents as demonstrated by scanning electron microscopy. The DCDNP stents were characterized for the release kinetics of plasmid DNA, and further evaluated for gene delivery and expression both in vitro and in vivo. In cell culture, DCDNP stents containing plasmid EGFP-C1 exhibited high level of GFP expression in cells grown on the stent surface and along the adjacent area. In animal studies, reporter gene activity was observed in the region of the artery in contact with the DCDNP stents, but not in adjacent arterial segments or distal organs. The DCDNP stent provides a very promising strategy for cardiovascular gene therapy

The value of CT-based radiomics in predicting the prognosis of acute pancreatitis

PurposeEarly judgment of the progress of acute pancreatitis (AP) and timely intervention are crucial to the prognosis of patients. The purpose of this study was to investigate the application value of CT-based radiomics of pancreatic parenchyma in predicting the prognosis of early AP.Materials and methodsThis retrospective study enrolled 137 patients diagnosed with AP (95 cases in the progressive group and 42 cases in the non-progressive group) who underwent CT scans. Patients were randomly divided into a training set (n = 95) and a validation set (n = 42) in a ratio of 7: 3. The region of interest (ROI) was outlined along the inner edge of the pancreatic parenchyma manually, and the Modified CT Severity Index (MCTSI) was assessed. After resampling and normalizing the CT image, a total of 2,264 radiomics features were extracted from the ROI. The radiomics features were downscaled and filtered using minimum redundancy maximum correlation (mRMR) and the least absolute shrinkage and selection operator algorithm (LASSO) regression, in turn, and the more optimal subset of radiomics features was selected. In addition, the radiomics score (rad-score) was calculated for each patient by the LASSO method. Clinical data were also analyzed to predict the prognosis of AP. Three prediction models, including clinical model, radiomics model, and combined clinical–radiomics model, are constructed. The effectiveness of each model was evaluated using receiver operating characteristic (ROC) curve analysis. The DeLong test was employed to compare the differences between the ROC curves. The decision curve analysis (DCA) is used to assess the net benefit of the model.ResultsThe mRMR algorithm and LASSO regression were used to select 13 radiomics features with high values. The rad-score of each texture feature was calculated to fuse MCTSI to establish the radiomics model, and both the clinical model and clinical–radiomics model were established. The clinical–radiomics model showed the best performance, the AUC and 95% confidence interval, accuracy, sensitivity, and specificity of the clinical–radiomics model in the training set were 0.984 (0.964–1.000), 0.947, 0.955, and 0.931, respectively. In the validation set, they were 0.942 (0.870–1.000), 0.929, 0.966, and 0.846, respectively. The Delong test showed that the predictive efficacy of the clinical–radiomics model was higher than that of the clinical model (Z = 2.767, p = 0.005) and the radiomics model (Z = 2.033, p = 0.042) in the validation set. Decision curve analysis demonstrated higher net clinical benefit for the clinical–radiomics model.ConclusionThe pancreatic parenchymal CT clinical–radiomics model has high diagnostic efficacy in predicting the progression of early AP patients, which is significantly better than the clinical or radiomics model. The combined model can help identify and determine the progression trend of patients with AP and improve the prognosis and survival of patients as early as possible

Reabilitação protética da disfunção velofaríngea: prótese de palato e obturador faríngeo

The seed maturation program only occurs during late embryogenesis, and repression of the program is pivotal for seedling development. However, the mechanism through which this repression is achieved in vegetative tissues is poorly understood. Here we report a microRNA (miRNA)-mediated repression mechanism operating in leaves. To understand the repression of the embryonic program in seedlings, we have conducted a genetic screen using a seed maturation gene reporter transgenic line in Arabidopsis (Arabidopsis thaliana) for the isolation of mutants that ectopically express seed maturation genes in leaves. One of the mutants identified from the screen is a weak allele of ARGONAUTE1 (AGO1) that encodes an effector protein for small RNAs. We first show that it is the defect in the accumulation of miRNAs rather than other small RNAs that causes the ectopic seed gene expression in ago1. We then demonstrate that overexpression of miR166 suppresses the derepression of the seed gene reporter in ago1 and that, conversely, the specific loss of miR166 causes ectopic expression of seed maturation genes. Further, we show that ectopic expression of miR166 targets, type III homeodomain-leucine zipper (HD-ZIPIII) genes PHABULOSA (PHB) and PHAVOLUTA (PHV), is sufficient to activate seed maturation genes in vegetative tissues. Lastly, we show that PHB binds the promoter of LEAFY COTYLEDON2 (LEC2), which encodes a master regulator of seed maturation. Therefore, this study establishes a core module composed of a miRNA, its target genes (PHB and PHV), and the direct target of PHB (LEC2) as an underlying mechanism that keeps the seed maturation program off during vegetative development