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Quantitative data acquisition of the drug induced cell apoptosis is one of the most important aspects of anticancer drug assessment. Traditional methods using photo-bleachable organic dyes to detect the apoptotic cells, may lead to some difficulties in long time observation of the cells. Moreover, the culture plates inevitably require large number of cells resulting in inefficiency in analysis of fewer cell samples such as a patient's own cells. To address these problems, we developed a microfluidic platform to assess the adherent cell cytotoxicity for anticancer drug screening using Annexin V conjugated quantum dots and Calcein AM as dual apoptotic probes. The results showed that camptothecin possessed more potent cytotoxic effect on these adherent tumor cells. Interestingly, the MCF-7 exhibited a certain resistance to these two anti-tumor drugs. For the first time, we achieved the evaluation of the impacts of model anti-cancer drugs on different adherent tumor cell lines using bio-functional quantum dots probe based cytotoxicity assays in a microfluidic device.

The response of the lamellar spacing to abrupt change of the solidifying rate for Al-Si eutectic during directional solidification has been investigated both experimentally and theoretically. When the solidifying rate was changed abruptly, the response of the lamellar spacing was gradual and retarded, which was attributed to the “cluster branching” and “cluster terminating” mechanisms of the lamellar phases. The retarded distance, as a function of the abrupt change factor, ρ, for both ρ>1 and ρ

Ba2NaNb5O15 (BNN) films on (001)-oriented KTiOPO4 (KTP) substrates were prepared by excimer laser ablation. Characterization of the films by the X-ray diffraction and scanning electron microscopy revealed that the films as prepared at 700°C and then cooled rapidly were (100) oriented, and a low density of micro twined substructures appeared in the films. As the films were annealed at 700°C and then cooled slowly through the ferro-elastic transition point (222)-oriented twined substructures in the films were identified. Besides the dominant set of waveguiding multimodes, a new set of m-lines which are attributed to the micro-twined substructures were observed. Favorable waveguiding property of the films were demonstrated by measurement of the optical propagating loss lower than 1.0dB/cm.

Waveguiding epitaxial Ba2NaNb5O15 films have been prepared on (010)-oriented KTiOPO4 substrates by a pulsed laser deposition technique. The as-grown films were characterized by an x-ray diffraction technique, scanning electron microscopy and polarized light microscopy, which revealed that epitaxial (001)-oriented Ba2NaNb5O15 films with small surface roughness were achieved on (010)-oriented KTiOPO4 substrates. X-ray photoelectron spectroscopy was employed to determine the chemical constitution of the as-grown films. Favourable optical waveguiding properties were demonstrated by m-line and light propagation loss measurements of TM and TE multimodes.

In situ surface enhanced infrared absorption spectroscopy (SEIRAS) with an attenuated total reflection (ATR) configuration has been used to monitor the adsorption kinetics of bovine hemoglobin (BHb) on a Au nanoparticle (NP) film. The IR absorbance for BHb molecules on a gold nanoparticle film deposited on a Si hemispherical optical window is about 58 times higher than that on a bare Si optical window and the detection sensitivity has been improved by 3 orders of magnitude. From the IR signal as a function of adsorption time, the adsorption kinetics and thermodynamics can be explored in situ. It is found that both the electrostatic interaction and the coordination bonds between BHb residues and Au NP film surface affect the adsorption kinetics. The maximum adsorption can be obtained in solution pH 7.0 (close to the isoelectric point of the protein) due to the electrostatic interaction among proteins. In addition, the isotherm of BHb adsorption follows well the Freundlich adsorption model.

Continuous plasma separation will be greatly helpful for dynamic metabolite monitoring in kinetics research and drug development. In this work, we proposed a continuous on-chip plasma separation method based on the natural aggregating and sedimentation behavior of red blood cells at low shear rate. In this approach, a glass capillary was first used to realize quick and obvious delamination of blood cells from plasma. A novel "dual-elbow" connector was designed to change the direction of delamination. The blood was finally separated by laminar flow and bifurcation on the microchip. Results demonstrated that the present device can efficiently and stably separate plasma from blood in a continuous means, e.g., in a 4 h separation we did not observe clogging or a trend of clogging. In addition, the present approach can avoid the damage to cells which usually occurs in separation with high shear rate in a microchannel and possible contaminants to plasma. The proposed microchip device is robust, simple, and inexpensive for long time plasma separation with high plasma recovery and less sample consumption. The present work provides an effective tool for metabolite monitoring in pharmacokinetics research and drug development.

Waveguiding LiNbO 3 films were prepared on sapphire substrates by excimer laser ablation. The as-grown films were characterized by XRD and SEM techniques, which revealed that epitaxial c -oriented and a -oriented LiNbO 3 films were achieved on (001) and (012) sapphire substrates, respectively. The optical waveguiding properties were demonstrated by measuring the TM and TE modes.

The manganese distribution in Cu-0.2at%Mn solid solution alloys after recrystallization at 818 K for 90 min has been measured by atom-probe FIM technique. Even in such a dilute solid solution, a non-uniform distribution on Mn is found. The Mn-rich regions have the size of a few nanometers to several tens of nanometers and the concentration of Mn varies within a wide range. A possible mechanism responsible for the formation of the non-uniform distribution is discussed. Due to the interaction with the grain boundaries and a low diffusivity in copper, Mn atoms are dragged by moving grain boundaries to form Mn-rich regions, which fall behind the moving boundaries and form a non-uniform concentration distribution during recrystallization.

Unit operations for complicated biochemical analysis cannot usually be integrated into one substrate. A possible solution to solve this problem is to integrate multi-unit operations into two or more substrates. In this case, transporting droplets from one substrate to another is essential. In this work, a new method to transport droplets from a hydrophobic glass substrate to a piezoelectric substrate is proposed. An interdigitated transducer (IDT) and reflectors were fabricated on an optic grade 128° YX-cut lithium niobate (LiNbO3) substrate, and its working surface between the IDT and a reflector was modified to be hydrophobic. Droplets to be transported were first pipetted onto a glass substrate. Adjust the glass substrate so that the droplets could contact the working surface of the piezoelectric substrate, and then was moved down. These droplets could be successfully transported from the glass surface to the piezoelectric substrate because of their “adhesion work” difference. By using this mechanism, water and red dye droplets were successfully transported from glass substrate to piezoelectric substrate. As an application, droplets mixing process was demonstrated in the piezoelectric substrate by using surface acoustic wave after they have been transported from the glass substrate.

To understand the fundamentals of enzymatic reactions confined in micro-/nanosystems, the construction of a small enzyme reactor coupled with an integrated real-time detection system for monitoring the kinetic information is a significant challenge. Nano-enzyme array reactors were fabricated by covalently linking enzymes to the inner channels of a porous anodic alumina (PAA) membrane. The mechanical stability of this nanodevice enables us to integrate an electrochemical detector for the real-time monitoring of the formation of the enzyme reaction product by sputtering a thin Pt film on one side of the PAA membrane. Because the enzymatic reaction is confined in a limited nanospace, the mass transport of the substrate would influence the reaction kinetics considerably. Therefore, the oxidation of glucose by dissolved oxygen catalyzed by immobilized glucose oxidase was used as a model to investigate the mass-transport-related enzymatic reaction kinetics in confined nanospaces. The activity and stability of the enzyme immobilized in the nanochannels was enhanced. In this nano-enzyme reactor, the enzymatic reaction was controlled by mass transport if the flux was low. With an increase in the flux (e.g., >50 microL min(-1)), the enzymatic reaction kinetics became the rate-determining step. This change resulted in the decrease in the conversion efficiency of the nano-enzyme reactor and the apparent Michaelis-Menten constant with an increase in substrate flux. This nanodevice integrated with an electrochemical detector could help to understand the fundamentals of enzymatic reactions confined in nanospaces and provide a platform for the design of highly efficient enzyme reactors. In addition, we believe that such nanodevices will find widespread applications in biosensing, drug screening, and biochemical synthesis.

Hybrid chips combing microchips with capillaries have displayed particular advantages in achieving UV-vis and mass spectroscopic detection. In this work, systematic 3-D numerical simulations have been carried out to explore the influence of junction interface cross-sectional area and ζ-potential distribution on sample band broadening in hybrid-chip electrophoresis separation. In this case, the ratio of cross-sectional area of chip to capillary channel (S(ratio) ) is used as the parameter of the variation in junction interface cross-sectional area. Theoretical simulations demonstrated that the decrease of the S(ratio) would increase the separation efficiency in the hybrid-chip-based CE with uniform ζ-potential distribution. ζ-potential distribution along the axial direction of the channel also affects mass transport in hybrid-chip-based CE. Therefore, the effect of ζ-potential distribution has been considered in the 3-D simulation. Theoretical simulation results reveal that ζ-potential distribution rather than the interface cross-sectional area variation (S(ratio) ) controls the sample band broadening and manipulates sample separation efficiency in the hybrid-chip-based CE with non-uniform ζ-potential distribution. Both the theoretical simulations and experimental results show that optimal hybrid-chip CE separation efficiency can be achieved at S(ratio) =1.

To study the prevalence of internet use and internet addiction in adolescents of Shanghai.From September to October 2007, a total of 5135 adolescents from 16 middle schools of 6 districts of Shanghai took part in the epidemiological study by a cross-sectional survey and 5123 adolescents finally enrolled in the study. A questionnaire of "DRM Adolescent Internet Use 52 Scale" was administrated to investigate the prevalence of internet use and internet addiction in adolescents of Shanghai. On this scale of 5-point rating, the scale includes seven parts of contents as tolerance, abstinence reaction, planning ability, self-control ability, whenness, sociability and hazard.The rate of internet use among the surveyed adolescents was 94.32% (4673/5123), among which the incidence rate of internet addiction was 8.78% (450/5123). Boys, senior middle-school students were more susceptible to internet addiction than girls and junior middle-school students (male scores 122.42+/-43.46, female scores 116.92+/-38.10, F=23.22, P=0.00; senior middle-school students 125.24+/-39.02, junior middle-school students 110.30+/-42.35, F=164.68, P=0.00). Students from vocational senior middle-school were most susceptible (junior middle-school students 110.30+/-42.35, ordinary senior middle-school students 122.83+/-40.99, key senior middle-school students 120.05+/-37.87, vocational senior middle-school students 133.37+/-36.84, F=34.44, P=0.00). The 2nd grade students of senior middle-school have the highest risk for internet-addiction.The prevalence of internet use and internet addiction in adolescents of Shanghai should be comparatively high in China, which indicates that great attention should be paid to the prevention and control.

New methods for fabricating highly -oriented and complete -textured Pb(Ta0.05Zr0.48Ti0.47)O3 (PTZT) films on Pt/TiO2/SiO2/Si(001) substrates by pulsed-laser deposition have been developed using conductive oxide La0.25Sr0.75CoO3 and SrRuO3 electrodes. The -preferred orientated PTZT ferroelectric capacitor was not subjected to loss of its polarization after 1×1010 switching cycles at an applied voltage of 5 V and a frequency of 1 MHz, and the -textured PTZT film capacitor retains 94.7% of its polarization after 1.5×1010 switching cycles at 5 V and 50 kHz. The PTZT capacitors using these conductive oxide electrodes have low leakage current dominated by Schottky field emission mechanism.

Objective : To investigate the status of human parasites in children who have been evacuated here from Yushu after earthquake . Methods : Detect the eggs from smear feces samples. Results : 512 stool samples were collected and examined by microscope. The total infection rate was 6.05%, where the infection rate for entamoeba coli Grassi was 3.91%, Giardia lamblia stile was 1.56%, Ascaris Lumbricoides was 0.59%. Conclusion : Our results suggest that the infection rate of human parasites is not higher than normal rate in China.

The ferroelectric Pb(Zr0.88Ti0.12)O3 (PZT)/conductive La0.5Sr0.5CoO3 (LSCO) hetero-structures have been prepared on (001) LaAlO3 (LAO) and (001) Si single crystal substrates by using pulsed laser deposition (PLD) technique. X-ray differactions showed that the PZT and LSCO layers are single phased with distorted perovskite structure, respectively. The heterostructure on (001) LAO is highly 〈001〉 oriented, whereas the heterostructure on (001) Si is poly-crystalline having double texture of 〈001〉 and 〈110〉. With the help of XPS analysis the compositions of PZT film have been determined. Using the LSCO film as bottom electrode the ferroelectric hysteresis of the PZT film has been measured.

A sensitive approach to the determination of reactive oxygen species (ROS) in puffs of cigarette smoke (CS) has been developed. The experimental system consists of a microfluidic chip electrophoresis and a laser induced fluorescence (LIF) device enhanced by localized surface plasmon resonance. Core-shell Ag@SiO2 nanoparticles were prepared and then immobilized on the surface of the microchannel to increase the fluorescence intensity based on localized surface plasmon resonance-enhanced fluorescence (LSPREF) effect. The ROS in puffs of CS were trapped via the oxidation of 2',7'-dichlorodihydrofluorescein (DCHF) that had been loaded on polyacrylonitrile (PAN) nanofibers in a micro-column. Determination of ROS was based on the amount of 2',7'-dichlorofluorescein (DCF), which is the sole product from DCHF oxidation. With the optimization of the trapping efficiency, we detected about 8.0 pmol of ROS per puff in the mainstream CS. This microchip electrophoresis-SPREF system enables sensitive quantitation of ROS in CS with low consumption of reagent, material, and analysis time.

In this study, we demonstrate a more sensitive colorimetric assay for the detection of melamine based on the strong attraction between exocyclic amine groups of melamine and surface-bound AuCl(4)(-)/AuCl(2)(-) ions on bare gold nanoparticles prepared by the borohydride reduction method. This method is rather simple without further modification of gold nanoparticles and complicated pretreatment of samples. The detection limit of the method is 2.0 × 10(-7) g L(-1) for melamine in infant formula, which is much lower (about 1000-fold) than that of using citrate-capped GNPs as a colorimetric probe. The proposed scheme could be a good alternative means for on-site and real-time screening of melamine adulterant in infant formula without costly instruments.

Herein, we report a method to investigate the thermodynamics and kinetics of immobilized enzyme (Glucose Oxidase, GOD) catalytic reaction on a microfluidics platform with precise temperature-control using a home-made plexiglass temperature controllable holder. This approach allows us to extract kinetic and thermodynamic parameters of the immobilized enzyme catalytic reactions easily, showing significant advantages over the traditional calorimetric and microcalorimetric methods which require complex fabrication of thermally isolated system. In our approach, the Arrhenius equation is introduced to establish the relationship between the kinetics and thermodynamics of the immobilized GOD. Results show that the obtained activation energy (Ea = 60.56 kJ mol−1) and the activation enthalpy (ΔHa = 53.08 kJ mol−1) are smaller than free enzymes, demonstrating that the immobilized GOD exhibits improved thermal stability compared with free enzymes. The present work offers an alternative approach to achieve the kinetics and thermodynamics of immobilized enzyme catalytic reactions on a microfluidics chip and promote our understanding of enzyme catalytic reactions.

In the present paper, an improvement on the traditional treatment method for moire data is made, and the so-called surface-fitting process is used to treat the moire data. A method of measurement of J- integrals from moire data is proposed, which can be used for pressure vessels and other shell structures. By means of the proposed method, J- integrals of different contours are calculated with centrally cracked wide plates under different loading conditions. The J- integrals calculated by the proposed method are in good agreement with those calculated by the Rice formula, both being based upon the present authors' same experiments.

A proposal related to experimental fracture mechanics suggested by Professor W. Soete, Gent University, Belgium, is investigated in the present paper. The concept of two critical crack lengths of general yield is proposed, and their physical meaning and engineering application are presented. Based on the experiment and analysis, an engineering method for the assessment of defects in pressure vessels is suggested.