Self assembly for surface functionalization to improve biocompatibilities in Ti-based implants and enzyme immobilization in biofuel cells

PhDSelf-assembly is an effective biomimetic technique for surface functionalization and nanostructural synthesis. 3-Aminopropyltriethoxysilane (APTES) is a popular molecule that can assemble over substrates to modify surface properties. Titanium is a structural material with high weight-specific mechanical properties, corrosion-resistance and bioinertness. Here, a systematic investigation was carried out to optimize the self-assembly of an APTES-modified film on an oxidized titanium surface in order to improve its biocompatibility as an implant material and molecular selectivity, e.g. for CO2 capture. A clean TiOx layer was formed on titanium after the treatment in a Piranha solution of H2SO4 : H2O2 = 3:1. The IR spectra confirmed that the formation of the APTES-modified film (called APS film) on the surface by the presence of the Si-O-Ti and Si-O-Si covalent bonds. The ordering of the self-assembled film did not show strong temperature dependence from 30 to 70ºC, although a thicker film was noted at a higher temperature. Anhydrous toluene as the solvent is essential to the formation of a well-ordered and thin film, compared with hydrous toluene. The well-assembled film was formed on the oxidised titanium surface in the anhydrous toluene solution of ~0.2 v% APTES at 30°C for 16 hours. A higher APTES concentration leads to a disorder film with protonated –NH3 + groups, whereas a lower concentration causes end groups of the adsorbed APTES to loop with the -OH groups on the surface. The APS film with the free –NH2 functional groups is more stable in aqueous solution with pH 10, although it is still hydrolyzed according to the intensity of the –Si-O-Si- bond in the IR spectra. The well-ordered APS film with the –NH2 groups cannot induce heterogeneous nucleation in a simulated body fluid (SBF), because the –NH2 groups are neutral in the solution and the –CH2- hydrophobic groups are exposed in the disordered structure of the APS film. In the application of biofuel cells, the laccase from Trametes versicolor as an enzyme was immobilized on titanium and graphite with the APS film by the covalent bond, respectively. Compared with the native laccase, optimum pH of the immobilized laccase decreased to 3 because of the increase of turnover number (Kcat). Further comparison of Michaelis-Menten constant (Km) of the immobilized laccase with the native one clearly shows that the increase of Km value is mainly due to the change of configuration of the active site, further leading to the lower affinity of immobilized laccase towards the substrate. The laccase on graphite shows higher optimum temperature and twice lower the Km value, compared with the laccase on titanium, which results from the surface morphology of graphite after oxidation. For electrochemical behaviour, graphite with the laccase as electrode does not show direct electron transfer (DET), due to the long electron tunnel between the T1 centre and electrode surface. However, the electrode with laccase shows good mediator electron transfer (MET) in the presence of mediator

Study on Xiangyang's population and aging trend prediction based on discrete population development equation model

Abstract Population problem is an important factor that influences economy and social development of China. This paper takes the statistic data of 6th census in 2010 in Xiangyang as the accordance to establish a discrete model of population development equation, to analyse the population aging trend in the future in Xiangyang from a short period, and further to predict the long-term population development trend and aging population change condition in Xiangyang in the case of different total fertility rate to provide reference accordance for the government to make relevant social and economic decisions

Tie-dye technique and pattern features

Relationship between tie-dye technique and image pattern has been studied. Based on digital image processing, average value of HSV (hue, saturation, value) tri-component of valid tie-dye area, proportion of incompletely dyed area in HSV color space and the Tamura first three texture features of digital tie-dye image have been extracted. Then, the repeated tests and analysis of variance (ANOVA) of rotation speed and concentration have been done. The results show the obvious impact of concentration and rotation speed on the color and texture feature of tie-dye pattern. Furthermore, back propagation neutral network is developed and partial pattern features with low correlation is used to forecast the tie-dye concentration and rotation speed. The experiment results show the 100% rate of forecast, which proves that pattern features can effectively achieve the technique forecast

Experimental cyclic inter-conversion between Coherence and Quantum Correlations

Quantum resource theories seek to quantify sources of non-classicality that bestow quantum technologies their operational advantage. Chief among these are studies of quantum correlations and quantum coherence. The former to isolate non-classicality in the correlations between systems, the latter to capture non-classicality of quantum superpositions within a single physical system. Here we present a scheme that cyclically inter-converts between these resources without loss. The first stage converts coherence present in an input system into correlations with an ancilla. The second stage harnesses these correlations to restore coherence on the input system by measurement of the ancilla. We experimentally demonstrate this inter-conversion process using linear optics. Our experiment highlights the connection between non-classicality of correlations and non-classicality within local quantum systems, and provides potential flexibilities in exploiting one resource to perform tasks normally associated with the other.Comment: 8 pages, 4 figures, comments welcom

Atomic-Scale Investigation on the Ultra-large Bending Behaviours of Layered Sodium Titanate Nanowires

Study on mechanical properties of one-dimensional layered titanate nanomaterials is crucial since they demonstrate important applications in various fields. Here, we conducted ex situ and in situ atomic-scale investigation on bending properties of a kind of ceramic layered titanate (Na2Ti2O4(OH)2) nanowires in a transmission electron microscopy. The nanowires showed flexibility along direction and could obtain a maximum bending strain of nearly 37%. By analysing the defect behaviours, the unique bending properties of this ceramic material was found to correlate with a novel arrangement of dislocations, an accessible nucleation and movement along the axial direction resulting from the weak electrostatic interaction between the TiO6 layers and the low b/a ratio. These results provide pioneering and key understanding on bending behaviours of layered titanate nanowire families and potentially other one-dimensional nanomaterials with layered crystalline structures.Comment: 9 pages, 5 figure

Original Article Differentiation of immortalized human precartilaginous stem cells into nucleus pulposus-like cells

Abstract: Objective: We aimed to explore the differentiation of immortalized human precartilaginous stem cells (IPSCs) into nucleus pulposus (NP)-like cells induced by transforming growth factor-β 1 (TGF-β 1 ) and examine its biological characteristics. Methods: The IPSCs were seeded onto chitosan/glycerophosphate (C/GP) scaffolds and induced into NP-like cells by adding TGF-β 1 under hypoxic conditions. The growth and differentiation of IPSCs were observed, and the formation of glycosaminoglycans (GAG) in the extracellular matrix of differentiating cells was detected by Alcian Blue staining. The expressions of type II collagen and aggrecan genes in NP-like cells were examined by reverse transcription-polymerase chain reaction (RT-PCR). The expressions of Sox9 and β-catenin were analyzed by Western blotting. Results: The IPSCs were observed to grow well on the C/GP scaffolds. After 7 days, Alcian Blue staining demonstrated the formation of GAG. The RT-PCR results showed that expression of type II collagen and aggrecan were upregulated compared with control group (P < 0.05, P < 0.05). Likewise, western blotting results showed that the expression of Sox9 and β-catenin was upregulated compared with control group (P < 0.05, P < 0.05). Conclusions: The findings demonstrate that IPSCs could be differentiated into NP-like cells following induction by TGF-β 1

Trmt112 Gene Expression in Mouse Embryonic Development

Mouse Trmt112, the homologous gene of yeast Trm112 (tRNA methyltransferase 11-2), was initially cloned from RIKEN with uncertain function. The yeast TRM112 is now known to play important roles in RNA methylation. Here, we studied the expression of Trmt112 by in situ hybridization and quantitative real-time RT-PCR (QRT-PCR). A higher expression level of Trmt112 was observed in the brain and nervous system by whole mount in situ hybridization from embryonic day 10.5 (E10.5) to E11.5. At later developmental stages E13.5 and E16.5, abundant expression was prominently found in various organs and tissues including developing brain, nervous system, thymus, lung, liver, intestine, kidney, and cartilage. Furthermore, Trmt112 was persistently expressed from E9.5 to E18.5 on whole embryos and highly expressed in multiple organs at E12.5, E15.5 and E18.5 by QRT-PCR. These results showed that Trmt112 gene was highly and ubiquitously expressed during mouse embryonic development, implying that it might be involved in the morphogenesis of diverse organs and tissues and numerous physiological functions

iASPP regulates neurite development by interacting with Spectrin proteins

IntroductionSince its discovery in 1999, a substantial body of research has shown that iASPP is highly expressed in various kinds of tumors, interacts with p53, and promotes cancer cell survival by antagonizing the apoptotic activity of p53. However, its role in neurodevelopment is still unknown.MethodsWe studied the role of iASPP in neuronal differentiation through different neuronal differentiation cellular models, combined with immunohistochemistry, RNA interference and gene overexpression, and studied the molecular mechanism involved in the regulation of neuronal development by iASPP through coimmunoprecipitation coupled with mass spectrometry (CoIP-MS) and coimmunoprecipitation (CoIP).ResultsIn this study, we found that the expression of iASPP gradually decreased during neuronal development. iASPP silencing promotes neuronal differentiation, while its overexpression inhibited neurite differentiation in a variety of neuronal differentiation cellular models. iASPP associated with the cytoskeleton-related protein Sptan1 and dephosphorylated the serine residues in the last spectrin repeat domain of Sptan1 by recruiting PP1. The non-phosphorylated and phosphomimetic mutant form of Sptbn1 inhibited and promoted neuronal cell development respectively.ConclusionOverall, we demonstrate that iASPP suppressed neurite development by inhibiting phosphorylation of Sptbn1

Online synchronous inspection and system optimization of flexible food packaging bags by using machine vision and sensing technique

Flexible food packaging in the market is increasingly favored, and its quality is essential and indispensable for safety and convenience.  However, quality inspection still stays in the manual stage, or partially manual inspection remains, in production, leading low efficiency, lack and even false inspection, hardly meeting the requirements of the modern output.  This paper proposes and optimizes the design of an automatic detection system with intelligence for flexible food packaging bag, which can effectively be adopted to check the quality of packaging trademark patterns, fillers, and sealing quality.  The inspection system runs with two-stage structure, machine vision, pressure sensing and synchronization to improve efficiency and ensure the normal production beat. Simplex Method is adopted to determine the best synchronous speeds online to achieve the best expectation. Comparison has been made between the manual inspection and our automatic operation, the sample of 10000 was statistically analyzed and results have shown that two workers were saved and the correctness rate of inspection raised up to 999.8‰