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A series of bis(arylidene)cycloalkanone photosensitizers modified by polyethylene glycol (PEG) have been studied for two-photon excited photodynamic therapy (2PE-PDT). As compared with their prototype compounds, these PEGylated photosensitizers show enhanced water solubilities while their photophysical and photochemical properties, including linear absorption, two-photon absorption, fluorescence, and singlet oxygen quantum yield, remain unaltered. In vitro behaviors (cellular uptake, subcellular localization, photocytotoxicity in both PDT and 2PE-PDT) of these photosensitizers reveal that an optimized lipid-water partition coefficient can be obtained by adjusting the length and position of the PEG chains. Among them, the photosensitizer modified asymmetrically by two tetraethylene glycol chains presents the best performance as a 2PE-PDT candidate. Selective blood-vessel closure and obvious therapeutic effect in inhibiting the growth of tumors are confirmed by in vivo 2PE-PDT after intravenous injection of this photosensitiezer. The survival periods of treated tumor-bearing mice are significantly prolonged. This study demonstrates the feasibility of using a simple molecule to construct a potential candidate for 2PE-PDT.

Hydrate plugging is a hidden threat to the safe exploitation of oil and gas. Inorganic salts are widely used as thermodynamic inhibitors to effectively prevent the hydrate formation. This study uses a molecular dynamics method to explore the mechanism of the hydrate dissociation via inorganic salts on the micro-scale. We simulated the dissociating process of methane hydrate under different concentration series of NaCl, KCl and CaCl2 solutions at 273 K, and analysed the changes of ionic structure, transport parameters and kinetic energy in the system of inorganic salt/hydrate. The simulation results successfully revealed the step-by-step dissociation of hydrate, and the differences in dissociation rates among the different inhibitors. The energy needed for hydrate dissociation alters for different inorganic solutions; the energy reaches maximum when KCl is the inhibitor, and lowest when the concentration of CaCl2 exceeds 30% w/w. We calculated the coordination numbers of all components, including o...

Chemotaxis has been shown to be beneficial for the migration of soil-inhabiting bacteria towards industrial chemical pollutants, which they degrade. Many studies have demonstrated the importance of this microbial property under various circumstances; however, few quantitative analyses have been undertaken to measure the two essential parameters that characterize the chemotaxis of bioremediation bacteria: the chemotactic sensitivity coefficient χ 0 and the chemotactic receptor constant Kc. The main challenge to determine these parameters is that χ 0 and Kc are coupled together in non-linear mathematical models used to evaluate them. In this study we developed a method to accurately measure these parameters for Pseudomonas putida in the presence of toluene, an important pollutant in groundwater contamination. Our approach uses a multilayer microfluidic device to expose bacteria to a convection-free linear chemical gradient of toluene that is stable over time. The bacterial distribution within the gradient is measured in terms of fluorescence intensity, and is then used to fit the parameters Kc and χ 0 with mathematical models. Critically, bacterial distributions under chemical gradients at two different concentrations were used to solve for both parameters independently. To validate the approach, the chemotaxis parameters of Escherichia coli strains towards α-methylaspartate were experimentally derived and were found to be consistent with published results from related work. Biotechnol. Bioeng. 2015;112: 896–904. © 2014 Wiley Periodicals, Inc.

Advanced Functional Materials, 28 (45), ISSN:1616-3028, ISSN:1616-301X

Shale interfacial properties are important for CO2 geo-sequestration and CH4 recovery in shale formation. In this work we use a newly-developed and well-defined shale model (i.e. a clay-coated quartz) to systematically evaluate the influence of kaolinite and montmorillonite, as primary constituents of shales, on CO2 shale-wettability, and shale-CO2, shale-CH4, and shale-water surface energies. Specifically, we measure CO2 wettability of clay-coated quartz and the related CO2-brine and CH4–brine interfacial tensions at various pressures and temperatures. We calculate the surface free energies of the clay-coated quartz versus CO2 and CH4 using Neumann’s equation. The results demonstrate that clay coating leads to a less hydrophilic surface at a low temperature (i.e. 300 K), while it renders the surface more hydrophilic at a high temperature (i.e. 353 K); however, clay coating has only a small influence on the quartz-CO2 and quartz-CH4 surface energies. In addition, higher CO2 pressures always result in less water-wet surfaces for clean, kaolinite-coated and montmorillonite-coated quartz samples at the temperatures tested (i.e. 300 K and 353 K). Moreover, higher CO2 and CH4 pressures lead to smaller mineral-CO2 and mineral-CH4 surface energies, respectively. An increase in temperature shows a complicated effect, i.e. it increases the surface energies of mineral-CO2 while it reduces those of mineral-CH4 (slightly) and clay-coated quartz-brine systems. For similar pressure and temperature values, the surface energies of mineral-CO2 system are always smaller than those of the corresponding mineral-CH4 systems. The results can aid the predictions of CO2 storage capacity, leakage risk assessments, and CH4 recovery.

The urban water environment rehabilitation project is a comprehensive strategic social project with large investment, wide scope and complicated construction conditions, which determines the uncertainty and particularity of the quality management of urban water environment rehabilitation projects. In order to improve the quality management level of urban water environment rehabilitation projects and promote urban water environment rehabilitation, this paper analyzes the characteristics of quality management of urban water environment rehabilitation projects from the viewpoint of the total quality management. Taking the Maozhou River urban water environment rehabilitation project in Shenzhen, Guangdong, China as an example, using the total quality management theory and causal analysis, the authors summed up the new quality management model, dual-collaborative quality management, for the water environment rehabilitation project, and some new technologies such as resident supervision system, closed circuit television inspection and data analysis technology were applied.

Understanding the mechanisms of plant growth and morphogenesis is of importance, not only to the field of plant sciences but also in a broader agricultural and economical context, as plants provide important raw materials such as food, fiber, wood and fuel. Mathematical modeling and simulation can provide insights into intricate biomechanical growth mechanisms. Mechanical characterization at single cellular level is essential for providing quantitative model parameters. The dual-axis Cellular Force Microscope (CFM) provide many of these desired parameters by micro-indentation measurements. The dual-axis CFM integrates a MEMS force sensing technology with a piezoelectric nano-positioning system. The dual force feedback from the MEMS sensor allows the system to be used for arbitrary indentation angles and to accurately measure biological samples despite their curved surfaces. The accuracy of the dual-axis CFM is verified by measuring a force-standard with a certified stiffness of 15.15 N/m at indentation angles of 90° and 60°. The obtained stiffness measurements are 15.60 N/m and 14.63 N/m and differ from the calibrated value by 2.97% and 3.63%, respectively. Additionally, the dual-axis CFM offers topographic imaging which was used to visualize two hemispherical structures fabricated using two-photon photopolymerization with radii of 5 µm and 7.5 µm. The potential of the system to study plant cell mechanics at a single cell level is shown by indenting a Lilium longiflorum pollen tube along its axis at the tip. The topographical information combined with the recorded force feedback in axial and lateral directions show promising results for further mechanical characterization of plant cells using the dual-axis CFM.

Chemotaxis toward chemical pollutants provides a mechanism for bacteria to migrate to locations of high contamination, which may improve the effectiveness of bioremediation. A microfluidic device was designed to mimic the dissolution of an organic-phase contaminant from a single pore into a larger macropore representing a preferred pathway for microorganisms that are carried along by groundwater flow. The glass windows of the microfluidic device allowed direct image analysis of bacterial distributions within the vicinity of the organic contaminant. Concentrations of chemotactic bacteria P. putida F1 near the organic/aqueous interface were 25% greater than those of a nonchemotactic mutant in the vicinity of toluene for a fluid velocity of 0.5 m/d. For E. coli responding to phenol, the bacterial concentrations were 60% greater than the controls, also at a velocity of 0.5 m/d. Velocities in the macropore were varied over a range from 0.5 to 10 m/d, the lower end of which is typical of groundwater velocities. The accumulation of chemotactic bacteria near the NAPL chemoattractant source decreased as the fluid velocity increased. Good agreement between computer-based simulations, generated using reasonable values of the model parameters, and the experimental data for P. putida strains confirmed the contribution due to chemotaxis. The experimental data for E. coli required a larger chemotactic sensitivity coefficient than that for P. putida, which was consistent with parameter values reported in the literature.

The use of chemotactic bacteria in bioremediation may improve the efficiency and decrease the cost of restoration of contaminated groundwater system. However, most previous studies focused at the laboratory scale and could hardly apply to the field scale. In this study, a dimensionless equation was formulated to solve this problem. First, the main influential factors were extracted from previous researches and then one set of dimensionless numbers was obtained based on Buckingham theory. After collecting parameter values and supplementing missing data, Chemotaxis number (Ch), the ratio of accumulated bacterial concentration to its initial value, was correlated with a combination of dimensionless numbers. For a Chemotaxis number greater than one, the bioremediation strategy is expected to be effective, and chemotactic bacteria are expected to accumulate around nonqueous phase liquid (NAPL) contaminant sources efficiently.

e13118Background: TNBC is associated with increased mortality compared to other breast cancer sub-types. There is an urgent need to develop novel, low toxicity and effective therapies for TNBC. Met...

The development of miniaturized cell culture platforms for performing parallel cultures and combinatorial assays is important in cell biology from the single-cell level to the system level. In this paper we developed an integrated microfluidic cell-culture platform, Cell-microChip (Cell-microChip), for parallel analyses of the effects of microenvironmental cues (i.e., culture scaffolds) on different mammalian cells and their cellular responses to external stimuli. As a model study, we demonstrated the ability of culturing and assaying several mammalian cells, such as NIH 3T3 fibroblast, B16 melanoma and HeLa cell lines, in a parallel way. For functional assays, first we tested drug-induced apoptotic responses from different cell lines. As a second functional assay, we performed "on-chip" transfection of a reporter gene encoding an enhanced green fluorescent protein (EGFP) followed by live-cell imaging of transcriptional activation of cyclooxygenase 2 (Cox-2) expression. Collectively, our Cell-microChip approach demonstrated the capability to carry out parallel operations and the potential to further integrate advanced functions and applications in the broader space of combinatorial chemistry and biology.

We have successfully designed and fabricated an integrated microfluidic platform, the hESC-microChip, which is capable of reproducible and quantitative culture and analysis of individual hESC colonies in a semi-automated fashion. In this device, a serpentine microchannel allows pre-screening of dissociated hESC clusters, and six individually addressable cell culture chambers enable parallel hESC culture, as well as multiparameter analyses in sequence. In order to quantitatively monitor hESC proliferation and pluripotency status in real time, knock-in hESC lines with EGFP driven by the endogenous OCT4 promoter were constructed. On-chip immunoassays of several pluripotency markers were carried out to confirm that the hESC colonies maintained their pluripotency. For the first time, our studies demonstrated well characterized hESC culture and analysis in a microfluidic setting, as well as a proof-of-concept demonstration of parallel/multiparameter/real-time/automated examination of self-renewal and differentiation in the same device.

In this work, we report a novel method for the creation of superhydrophilic patterns on the surface of hydrophobically coated glass through CO2 laser cleaning. This mask-free approach requires no photolithography for the print of the features, and only a single-step surface pretreatment is needed. The laser-cleaned glass surface enables self-partitioning of liquid into droplet arrays with controllable, quantitative volumes. We further designed wall-less cell arrays for the mapping of culturing conditions and demonstrated the potential of this droplet-arraying method.

Advanced hydrogel systems that allow precise control of cells and their 3D microenvironments are needed in tissue engineering, disease modeling, and drug screening. Multiphoton lithography (MPL) allows true 3D microfabrication of complex objects, but its biological application requires a cell-compatible hydrogel resist that is sufficiently photosensitive, cell-degradable, and permissive to support 3D cell growth. Here, an extremely photosensitive cell-responsive hydrogel composed of peptide-crosslinked polyvinyl alcohol (PVA) is designed to expand the biological applications of MPL. PVA hydrogels are formed rapidly by ultraviolet light within 1 min in the presence of cells, providing fully synthetic matrices that are instructive for cell-matrix remodeling, multicellular morphogenesis, and protease-mediated cell invasion. By focusing a multiphoton laser into a cell-laden PVA hydrogel, cell-instructive extracellular cues are site-specifically attached to the PVA matrix. Cell invasion is thus precisely guided in 3D with micrometer-scale spatial resolution. This robust hydrogel enables, for the first time, ultrafast MPL of cell-responsive synthetic matrices at writing speeds up to 50 mm s-1 . This approach should enable facile photochemical construction and manipulation of 3D cellular microenvironments with unprecedented flexibility and precision.

The 3D fabrication of bio-compatible materials under an aqueous environment is a fundamental requirement for tissue engineering. In this work, a series of polyethylene glycol- (PEG-), carboxylate anionic group- or pyridyl cationic groupfunctionalized benzylidene cyclopentanone photo-initiators (B 2 , B 3 , X 2 , X 3 , Y 1 and P 1 ) were synthesized. Their water-solubility, photophysical properties and cytotoxicity were investigated. Using eosin as reference, their initiation efficiencies in water-soluble photoactive formulation (SR610 with 20% of DI water) excited by one- or two-photon were studied. The results showed that there were no significant differences on partial linear photophysical properties of these initiators, such as [see manuscript] and [see manuscript], but differences on their (see manuscript), Φ, and σ max are clear. In addition, their cytotoxicity is different. Two PEG-functionalized initiators (B 3 and X 3 ) with two PEG groups on one side of benzylidene cyclopentanone cores have obvious toxicity, while other four intiators are safety to HepG2 cells at the concentration of 20 μM. Moreover, the water-solubility of X 2 and X 3 (containing two longer PEG) were much better than those of other four initiators. Using these initiators, 3D micro-structures fabricated by two-photon polymerization of water-soluble acrylate all could be achieved. In addition, their threshold energies were all lower than 0.5 mW. However, the stiffness of 3D micro-structures was affected by the water-solubility of these photo-initiators. Those structures built by formulations containing X 2 and X 3 would collapse easily. Conversely, other structures could sustain very well. This work proves that B 2 ，Y 1 ，and P 1 have extensive application prospects in 3D fabrication for tissue engineering.

A series of amphiphilic benzylidene cycloalkanes ketone photosensitizers C1-C4 with or without folate receptor-targeted agent were designed and synthesized. Their photophysical properties and in vitro photodynamic therapy (PDT) effects were studied. The results showed that all compounds exhibited appropriate lipid-water partition coefficients and high reactive oxygen yields. The introduction of the folate receptor-targeted agent had no obvious influence on the basic photophysical & photochemical properties of C2 and C4 compared to those of their corresponding prototype compounds (C1 and C3). In vitro studies were carried out using MCF-7 cells (FR+), Hela cells (FR+) and A549 cells (FR-), which represented different levels of folate receptor (FR) expression. All of C1-C4 showed low dark toxicity and superior PDT effects compared with the clinical drug PSD-007 (a mixture of porphyrins). What’s more, folate receptor-targeted photosensitizers (C2 and C4) achieved higher accumulation and more excellent PDT effects in MCF-7 cells (FR+) and Hela cells (FR+) than photosensitizers (C1 and C3) without folate receptor-targeted agent and PSD-007. The photocytotoxicity of these photosensitizers showed no obvious differences in A549 cells (FR-).

Chemotaxis has been shown to be beneficial for the migration of soil-inhabiting bacteria towards industrial chemical pollutants, which they degrade. Many studies have demonstrated the importance of this microbial property under various circumstances; however, few quantitative analyses have been undertaken to measure the two essential parameters that characterize the chemotaxis of bioremediation bacteria: the chemotactic sensitivity coefficient χ(0) and the chemotactic receptor constant K(c). The main challenge to determine these parameters is that χ(0) and K(c) are coupled together in non-linear mathematical models used to evaluate them. In this study we developed a method to accurately measure these parameters for Pseudomonas putida in the presence of toluene, an important pollutant in groundwater contamination. Our approach uses a multilayer microfluidic device to expose bacteria to a convection-free linear chemical gradient of toluene that is stable over time. The bacterial distribution within the gradient is measured in terms of fluorescence intensity, and is then used to fit the parameters Kc and χ(0) with mathematical models. Critically, bacterial distributions under chemical gradients at two different concentrations were used to solve for both parameters independently. To validate the approach, the chemotaxis parameters of Escherichia coli strains towards α-methylaspartate were experimentally derived and were found to be consistent with published results from related work.

To assess the nutritional status of iodine in school children of Wuqiao County in Hebei Province.1209 school children aged 8-12 years were selected by multistage random sampling. Thyroid size estimated by inspection and palpation was graded according to the criteria recommended by WHO. The concentration of urinary iodine and iodine in salt was also measured.There were 74 goiter cases, accounted for 6.1% of total students investigated. The median of urinary iodine was 208 microg/L and the median of iodine intake was 312 microg/d. The excretion of urinary iodine at100 microg/L,50 microg/L, 200-300 microg/L and 300 microg/L accounted for 18.5%, 4.6%, 27.2% and 26.5% of total detected samples respectively. The coverage of iodized salt in the area was 77% and the iodine in iodized salt was at a median of 26.96 mg/kg.Goiter is endemic in Wuqiao County of Hebei Provinee. Urinary iodine of school children was more than the optimal range, and the iodine nutrition was excessive in this area.

Previously we have proposed a theoretical framework, named BayesOWL, which translates an OWL taxonomy of concept classes into a Bayesian network (BN) and incorporates consistent probabilistic information about the concept classes into the translated BN. In this paper, we extend the original framework to support general OWL DL ontologies and to effectively deal with inconsistent probabilistic information. We have also implemented the BayesOWL prototype system, which can be used as a practical tool by people investigating uncertainty in Semantic Web.

The experiment teaching is very important in a physics course. But the fact is students think and do little during the whole experiments. A virtual physics experiment teaching system (VPETS) with high degree of realism has been developed to improve the experiment teaching. This system enables students to use any PC to do virtual physics experiments just like doing real experiments. However, it can only be used for centralized teaching. With the rapid development of the Internet, a remote education assistant system (REAS) is developed to aid the VPETS to be used over the Internet. It extends the VPETS to an Internet version and realizes the management of the experiment reports over the Internet. The details of the REAS are described. It brought changes to conventional teaching ways and makes the experiment teaching much more open and original. Results show students favor its limitlessness of time and space and take the REAS course enthusiastically.

Proceedings of The 20th IEEE International Conference on Tools with Artificial Intelligence, This paper presents an efficient method, SMOOTH, for modifying a joint probability distribution to satisfy a set of inconsistent constraints. It extends the well-known “iterative proportional fitting procedure” (IPFP), which only works with consistent constraints. Comparing with existing methods, SMOOTH is computationally more efficient and insensitive to data. Moreover, SMOOTH can be easily integrated with Bayesian networks for Bayes reasoning with inconsistent constraints.

Magnetic helical microrobots that can be driven by low-strength rotating magnetic fields have found wide applications, particularly in biomedical research. The motion dynamics of magnetic helical microrobots is critical for their intelligent control and for performing different tasks in complex environments. These microrobots convert rotational motion into translational motion along their central axis. Many factors contribute to their swimming dynamics, such as the geometry of the helix, the thickness and properties of the coated magnetic layer, the viscosity of the fluid, and the wettability of the helix in the fluid. In this paper, we establish a comprehensive dynamic model to analyze the swimming properties of magnetic helical microrobots at low Reynolds numbers. The influence of different designs of magnetic helical microrobots on their swimming velocity, step-out frequency, and maximum velocity is comprehensively analyzed, for the first time, providing valuable guidance for the design of helical microrobots for different applications. Our results are supported by a number of experimental studies. ISSN:2377-3766