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Severe conjunctival diseases can cause significant conjunctival scarring, which seriously limits eye movement and affects patients' vision. Conjunctival reconstruction remains challenging due to the lack of efficient methods for stem cells enrichment. This study indicated that p75 positive conjunctival epithelial cells (CjECs) were mainly located in the basal layer of human conjunctival epithelium and showed an immature differentiation state in vivo. The p75 strongly positive (p75++) CjECs enriched by immuno‐magnetic beads exhibited high expression of stem cell markers and low expression of differentiated keratins. During continuous cell passage cultivation, p75++ CjECs showed the strongest proliferation potential and were able to reconstruct the conjunctiva in vivo with the most complete structure and function. Exogenous addition of NGF promoted the differentiation of CjECs by increasing nuclear localization of SALL2 in p75++ CjECs while proNGF played an opposite role. Altogether, p75++ CjECs present stem cell characteristics and exhibit the strongest proliferation potential so can be used as seed cells for conjunctival reconstruction, and NGF‐p75‐SALL2 signaling pathway was involved in regulating the differentiation of CjECs., p75++ CjECs(conjunctival epithelial cells) were enriched by immuno‐magnetic beads and their stem cell properties were detected. After 10 days of culture on amniotic membrane, conjunctiva constructed by p75++/− CjECs was transplanted to a rabbit model of conjunctival defect to test the repair effect. Exogenous addition of NGF promoted the differentiation of CjECs by increasing nuclear localization of SALL2 in p75++ CjECs.

Neovascularization during ocular tissue repair can cause severe visual loss in the optical axis and is therefore an issue of considerable concern to ophthalmologists. Here, we introduced a cholesterol-modified siRNA delivery system targeting stromal cell-derived factor 1 (SDF-1) to treat ocular angiogenesis in vivo. SDF-1 expression was analyzed in rat endothelial progenitor cells (EPCs) and bone marrow mesenchymal stem cells (BMSCs) using quantitative PCR (qPCR). Migration ability of BMSC and HUVEC were assessed through transwell assay. The proliferation effect of chol-siSDF1 on HUVEC was measured by colony formation assay. In vivo anti-angiogenic effects of chol-siSDF1 were tested in a cornea alkali burn model and the area of cornea neovascularization was measured using computer-imaging analysis system. Then phosphorylated Akt and total Akt protein levels were measured through western blot. Results turned out that rat EPCs and BMSCs showed high SDF-1 mRNA expression, which can be down-regulated by using chol-siSDF-1. Chol-siSDF-1 could significantly inhibit migration of BMSC and HUVEC. In addition, chol-siSDF1 also could inhibit HUVEC proliferation and exert a significant anti-angiogenic effect in corneal alkali burn model. As for the mechanism, chol-siSDF1 may inhibit the neovascularization, proliferation and metastasis through inhibiting the Akt signaling pathway. Thus, cholesterol modification of siRNA targeting SDF-1 displays an effective inhibition of migration and angiogenesis, with a much longer duration of inhibition effect.

Purpose To develop a new rabbit model of corneal endothelial injury using a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser. Methods The corneal endothelia of 2 groups of New Zealand white rabbits were treated with an Nd:YAG laser in a uniformly scattered fashion. Rabbits in group A underwent laser burns on the whole corneal endothelium, including the limbus area, whereas rabbits in group B were subjected to laser burns in the central 9-mm diameter zone of the endothelium. Slit-lamp biomicroscopy, optical coherence tomography, applanation tonometry, confocal microscopy, scanning electron microscopy, and histological examinations were performed during 4 weeks of follow-up. Results In both groups, dotted or focal corneal endothelium defects were directly observed. The stroma was intact. Right after laser application, a series of clinical manifestations appeared, including subepithelial and stromal edema, increased central corneal thickness, and corneal opacity. Laser burn had more notable effects in group A than in group B. In both groups, we observed no damage to the intraocular structures, and intraocular pressure was normal after laser treatment. Conclusions Nd:YAG laser treatment in a 9-mm diameter zone of the endothelium can effectively induce bullous keratopathy in a rabbit, whereas treatment for the entire corneal endothelium maintains bullous keratopathy for a longer period. The procedure is simple and reproducible, and it retains normal intraocular structures. This study provided a promising model for future research into endothelial cell damage and for the development of new therapies.

Recent research has demonstrated critical roles of a number of microRNAs (miRNAs) in stem cell proliferation and differentiation. miRNA-9 (miR-9) is a brain-enriched miRNA. Whether miR-9 has a role in retinal progenitor cell (RPC) proliferation and differentiation remains unknown. In this study, we show that miR-9 plays an important role in RPC fate determination. The expression of miR-9 was inversely correlated with that of the nuclear receptor TLX, which is an essential regulator of neural stem cell self-renewal. Overexpression of miR-9 downregulated the TLX levels in RPCs, leading to reduced RPC proliferation and increased neuronal and glial differentiation, and the effect of miR-9 overexpression on RPC proliferation and differentiation was inhibited by the TLX overexpression; knockdown of miR-9 resulted in increased TLX expression as well as enhanced proliferation of RPCs. Furthermore, inhibition of endogenous TLX by small interfering RNA suppressed RPC proliferation and promoted RPCs to differentiate into retinal neuronal and glial cells. These results suggest that miR-9 and TLX form a feedback regulatory loop to coordinate the proliferation and differentiation of retinal progenitors.

Polyethylene/paraffin oil blend sheets with different molecular weights of polyethylene were prepared by thermally induced phase separation. Isothermal and non-isothermal crystallization behaviors of blend sheets were investigated by differential scanning calorimetry (DSC). Isothermal DSC curves were analyzed by Avrami equation, whereas non-isothermal DSC curves were analyzed by Jeziorny method and Mo method. Effective activation energy (ΔE) of isothermal and non-isothermal crystallization was calculated by Friedman method. Under isothermal condition, value of n in Avrami equation hovered at 2.1, and lgZ increased with the decrease of crystallization temperature. lgZ and ΔE of blend sheets with a larger molecular weight of polyethylene was smaller than that of blend sheets with smaller molecular weight. Under non-isothermal condition, value of n obtained by Jeziorny method hovered at 2.4, close to n of isothermal condition. lgZ c increased with the increase of cooling rate and decrease of molecular weight of polyethylene. ΔE of different blend sheets were close to each other. Crystal structures of blend sheets formed under non-isothermal condition were analyzed by X-ray diffraction (XRD) analysis. XRD analysis showed that molecular weight of polyethylene and cooling rate had slight influence on crystal structure and crystallinity of polyethylene/paraffin oil blend sheet.

This paper presents a Chirplet Wigner–Ville Distribution (CWVD) that is free for cross-term that usually occurs in Wigner–Ville distribution (WVD). By transforming the signal with frequency rotating operators, several mono-frequency signals without intermittent are obtained, WVD is applied to the rotated signals that is cross-term free, then some frequency shift operators corresponding to the rotating operator are utilized to relocate the signal′s instantaneous frequencies (IFs). The operators′ parameters come from the estimation of the IFs which are approached with a polynomial functions or spline functions. What is more, by analysis of error, the main factors for the performance of the novel method have been discovered and an effective signal extending method based on the IFs estimation has been developed to improve the energy concentration of WVD. The excellent performance of the novel method was manifested by applying it to estimate the IFs of some numerical signals and the echolocation signal emitted by the Large Brown Bat.

The vibration signals of rolling element bearings are random cyclostationary when they have faults. Also, statistical properties of the signals change periodically with time. The accurate analysis of time-varying signals is an essential pre-requisite for the fault diagnosis and hence safe operation of rolling element bearings. The Wigner distribution is probably most widely used among the Cohen’s class in order to describe how the spectral content of a signal changes over time. However, the basic nature of such signals causes significant interfering cross-terms, which do not permit a straightforward interpretation of the energy distribution. To overcome this difficulty, the Wigner–Ville distribution (WVD) based on the cyclic spectral density (CSD) is discussed in this article. It is shown that the improved WVD, based on CSD of a long time series, can render the time–frequency distribution less susceptible to noise, and restrain the cross-terms in the time–frequency domain. Simulation and experiment of the rolling element-bearing fault diagnosis are performed, and the results indicate the validity of WVD based on CSD in time–frequency analysis for bearing fault detection.

In order to overcome the limitation of traditional near-field acoustical holography (NAH), that the sound field on one side of the holographic surface must be free, a sound field separation technique based on single holographic surface and wave superposition method (WSM) is proposed. According to the WSM, the field on and near the measurement surface may be approximated by the field produced by virtual source points placed on a surface inside the structure. The source strengths are evaluated by applying boundary conditions on the measurement surface. Here, the ‘pseudo’ sound pressure of the reconstruction surface is first obtained based on the principle of sound field mirror image and WSM, then the sound pressure of the target sound source acting on the holographic surface is separated by the sound pressures of the holographic surface and the reconstruction surface, and the sound field separation is realized. The technique requires the inversion of the Green's function matrix, which may be ill-conditioned. The Tikhonov regularization method is used to invert it, and the value of the regularization parameter is determined by the L-curve criteria. Through the numerical simulation and experiment, the results show the validity and efficiency of this technique.

Biocompatible polymer scaffolds are promising as potential carriers for the delivery of retinal progenitor cells (RPCs) in cell replacement therapy for the repair of damaged or diseased retinas. The primary goal of the present study was to investigate the effects of blended electrospun nanofibrous membranes of silk fibroin (SF) and poly(L-lactic acid-co-ε-caprolactone) (PLCL), a novel scaffold, on the biological behaviour of RPCs in vitro. To assess the cell-scaffold interaction, RPCs were cultured on SF/PLCL scaffolds for indicated durations. Our data revealed that all the SF/PLCL scaffolds were thoroughly cytocompatible and the SF:PLCL (1:1) scaffolds yielded the best RPC growth. The in vitro proliferation assays showed that RPCs proliferated more quickly on the SF:PLCL (1:1) than on the other scaffolds and the control. Quantitative polymerase chain reaction (qPCR) and immunocytochemistry analyses demonstrated that RPCs grown on the SF:PLCL (1:1) scaffolds preferentially differentiated toward retinal neurons, including, most interestingly, photoreceptors. In summary, we demonstrated that the SF:PLCL (1:1) scaffolds can not only markedly promote RPC proliferation with cytocompatibility for RPC growth but also robustly enhance RPCs’ differentiation toward specific retinal neurons of interest in vitro, suggesting that SF:PLCL (1:1) scaffolds may have potential applications in retinal cell replacement therapy in the future.

Corneal transparency is maintained by the corneal endothelium through its barrier and ionic pump function. However, this function could be compromised with age and variety of diseases and trauma, leading to cornea dycompensation, corneal edema, bullous keratopathy and even loss of visual acuity. So far, a lot of measures have been proposed to solve the problem through promoting the corneal endothelial cells (CECs) proliferation both in vivo and in vitro. However, the exact molecular mechanism regarding the proliferation potential as well as associated phenotype maintenance of CECs has not been well clarified. Accordingly, we will review the studies outlined the signal transduction pathways that were involved in the process of CECs proliferation, which is an important and relatively seldom touched research direction for future new therapies of corneal endothelium dysfunction. By operating the crucial signaling molecular in these pathways, we anticipate to activate or block the signaling pathways and thus help engineering CEC monolayer for clinical transplantation.

MicroRNAs manifest significant functions in brain neural stem cell (NSC) self-renewal and differentiation through the post-transcriptional regulation of neurogenesis genes. Let-7b is expressed in the mammalian brain and regulates NSC proliferation and differentiation by targeting the nuclear receptor TLX, which is an essential regulator of NSC self-renewal. Whether let-7b and TLX act as important regulators in retinal progenitor cell (RPC) proliferation and differentiation remains unknown. Here, our data show that let-7b and TLX play important roles in controlling RPC fate determination in vitro. Let-7b suppresses TLX expression to negatively regulate RPC proliferation and accelerate the neuronal and glial differentiation of RPCs. The overexpression of let-7b downregulates TLX levels in RPCs, leading to reduced RPC proliferation and increased neuronal and glial differentiation, whereas antisense knockdown of let-7b produces robust TLX expression,enhanced RPC proliferation and decreased differentiation. Moreover, the inhibition of endogenous TLX by small interfering RNA suppresses RPC proliferation and promotes RPC differentiation. Furthermore, overexpression of TLX rescues let-7b-induced proliferation deficiency and weakens the RPC differentiation enhancement caused by let-7b alone. These results suggest that let-7b, by forming a negative feedback loop with TLX, provides a novel model to regulate the proliferation and differentiation of retinal progenitors in vitro.

Purpose: To investigate the effect of the ATP-P2Y2-PI3K/Akt signaling axis on promoting rabbit corneal endothelial cell (RCEC) proliferation in vitro. Methods: Five concentrations of adenosine triphosphate (ATP; 1, 10, 25, 50 and 100 μM) were added to RCECs, and the cell proliferation was detected using Cell Counting Kit-8 (CCK8) and Ki67 immunohistochemical staining. Other P2Y2 receptor agonists and antagonists were added to the cells, and the proliferation effect was evaluated using CCK8 to determine the involvement of the P2Y2 receptor. Changes in the expression of phosphorylated Akt in RCECs treated with different concentrations of extracellular ATP and the duration of extracellular ATP on Akt phosphorylation were investigated using Western blotting. The pharmacological profiles with or without the PI3K/Akt pathway inhibitors were also determined using Western blotting. Results: We found that 10 μM ATP strongly promoted RCEC proliferation in vitro. Additionally, 25 μM ATP had a proliferation effect, whereas other concentrations (1, 50 and 100 μM) had no effect compared with the control group. Selective P2Y2 receptor agonists (UTP, ATPγS and Ap4A) showed the same promotion effect, while P2Y2 antagonists and PI3K/Akt inhibitors inhibited the effect of ATP. Moreover, phosphorylated Akt could be induced by the addition of extracellular ATP at all five concentrations and lasted for 1 h. This phosphorylation was prevented by PI3K/Akt inhibitors and a P2Y2 antagonist. Conclusions: These findings showed that 10 μM ATP markedly promoted RCEC proliferation via the P2Y2-PI3K/Akt signaling axis.

In this paper, using the information theory and the statistics analysis method, we have established the theory and method of faults diagnosis based on the multi-index fusion, including the information theory of multi-index diagnosis, diagnosis ability testing, indexes selecting, and Bayesian diagnosis modelling. And then, we applied the theories and methods to analyse the piston–liner wear condition of a diesel engine. In that, satisfactory results are achieved.

In this paper, some non-linear diagnostic methods for rotating machinery are introduced and evaluated from the view of diagnostic practice. The methods are pseudo-phase portrait, singular spectrum analysis and correlation dimension. The pseudo-phase portrait is simple, easy to draw, and is sensitive to some fault types. Singular spectrum analysis can reveal the complexity of a signal. By means of singular spectrum analysis one can reduce the noise of a signal. Correlation dimension can provide some intrinsic information of an underlying dynamical system, and can be used to classify different faults intelligently. Examples show that all these methods are advantageous in the field of non-linear diagnostics. Therefore, it is quite reasonable for effective fault diagnosis to use non-linear diagnostic methods in addition to the methods currently used, such as orbit portrait, FFT spectra, time–frequency analysis, etc.

This paper reports on the application of the correlation dimension in large rotating machinery fault diagnosis. The Grassberger-Procaccia algorithm and its modified version are introduced. Some important influencing factors relating directly to the computational precision of the correlation dimension are discussed. Industrial vibration signals measured from large rotating machinery with different faults are researched using the above-mentioned methods. The results show that the correlation dimension can provide some intrinsic information on an underlying dynamic system and can be used to classify different faults intelligently.