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In Kenya, the ‘Linda Mama Program’, a free care program for pregnant women, is being implemented, but as of 2017, maternal deaths per 100,000 live births reached 342, and the infection rate such as AIDS, hepatitis B, and syphilis is high. Diagnosis is being made centering on a quick simple test (rapid diagnosis), but the reliability is low, so an accurate and quick diagnosis method is needed. Through the Innovative Technology Program (CTS) of Korea International Cooperation Agency (KOICA), we developed a multi-immune diagnostic device and multi-diagnostic kit that can diagnose AIDS, hepatitis B, and syphilis, which can be tested with minimal education at schools and local public health centers in addition to hospitals. The sensitivity and specificity of the diagnostic kit were each 90% or more, which was improved by more than 20% compared to the rapid diagnostic kits. The supply of cost-competitive diagnostic devices and test kits will enable continuous monitoring of AIDS, hepatitis B, and syphilis infections among women of childbearing age between the ages of 15 and 49, thereby contributing to the improvement of maternal and child health.

In this paper we report the results on the optimization of the bi-layer lift-off resist (LOR) SiO2 sputter-deposition technique which is ideal for obtaining damage-free multi-electrode array (MEA). To optimize the bi-layer overhang formation, we have examined the undercut formation kinetics of LOR bottom layer and the dependence of the SiO2 sputter-deposition lift-off processed electrode structure on the undercut length. Crater-shaped and recessed electrode structure is obtained when the undercut length is short (≤2 μm) and longer than 3 μm, respectively. To optimize the SiO2 sputter-deposition process, we have examined the dependence of Au electrode passivation on the SiO2 sputtering parameters in terms of electrochemical cyclic-voltammogram (CV), impedance, electrical noise, sputter-deposition rate and in vitro neuronal activity recording property. The MEAs passivated under pure argon supply condition showed poor barrier properties, poor neuronal signal recording performance, and cytotoxic property. The CV of MEAs passivated under oxygen mixing ratios above 5% showed traditional sigmoidal CV and long-term recording of neuronal activities, probing the excellent barrier property and cytocompatibility of the SiO2 films sputter-deposited under oxygen mixing conditions. We have also issued thermal damaging aspect of bi-layer overhang structure which is tightly coupled with the detailed electrode structure and the high sputter-deposition rate. Finally, it was suggested that measurement of CV, electrochemical impedance and electrical noise can be a viable tool in evaluating the barrier performance of a passivation layer.

In this paper, we present a walking guidance system for the visually impaired for use at subway stations. This system, which is based on environmental knowledge, automatically detects and recognizes both exit numbers and arrow signs from natural outdoor scenes. The visually impaired can, therefore, utilize the system to find their own way (for example, using exit numbers and the directions provided) through a subway station. The proposed walking guidance system consists mainly of three stages: (a) sign detection using the MCT-based AdaBoost technique, (b) sign recognition using support vector machines and hidden Markov models, and (c) three verification techniques to discriminate between signs and non-signs. The experimental results indicate that our sign recognition system has a high performance with a detection rate of 98%, a recognition rate of 99.5%, and a false-positive error rate of 0.152.

We have synthesized photocrosslinkable benzophenone copolymer, Poly(St- co -MBz), and fabricated cell-repellent patterns of Poly(St- co -MBz) on covalently bound poly- d -lysine (PDL) layer via the photocrosslinking. We have successfully obtained fine grid line pattern with line width of 3 μm and fine neurite, presumably axon, patterns with excellent pattern fidelity. We found that benzophenone unit can be crosslinked under the exposure of UV (with the intensity of ∼77 mW/cm 2 at 280 nm and ∼60 mW/cm 2 at 365 nm) without photo-oxidative damage to PDL, poly- l -lysine, and polyethyleneimine.

We have prepared the poly-d-lysine (PDL) bound surfaces for neuron cell culture by covalent binding between the poly-d-Lysine and substrates and investigated neuronal cell adhesion properties and cell growth morphology. The number of neuronal cell and the number of neurite per neuronal cell on PDL bound surfaces was much more than those on PDL coated surfaces and also the neuronal cells on PDL bounded surfaces survived a longer time. On the pattern of covalently bound PDL, neuronal cells and their neurites are confined within the grid line leading to patterned neuronal networks with the long-term survival.

Here we describe a new analytical method for the detection of two influenza A viruses by nitrocellulose membrane and magnetic sensors that employ a special frequency mixing technique. The combination of the nitrocellulose membrane and magnetic bead detection permits a rapid assay procedure and excludes two steps (the development of color and the stop reaction) required for usual immunochemical detection methods such as ELISA. Quantitative virus detection was performed using magnetic beads conjugated with secondary antibody. The results were compared with conventional assay methods and with a dot-blot assay with fluorescence compound (FITC). Under optimum conditions, our new assay procedure is capable of detecting picograms of virus per well. This new method combining the nitrocellulose membrane and magnetic bead detection reduces analytical time and allows stable and repeatable analyses of samples in point-of-care applications.

This study was conducted to whether the administration of mexiletine, a Na+ channel blocker, impacts the recovery from demyelination. Under anesthesia, 0.1% ethidium bromide was injected into the dorsal funiculus (T3), followed by a mexiletine or saline treatment. Motor evoked potential (MEP) recordings and luxol fast blue stainings were performed at one, seven, 14, and 21 days post-operatively. Conduction was delayed during demyelination, but the mexiletine-injected group demonstrated shortened latencies and reductions in the demyelination area when compared to the control. These results suggest that systemic mexiletine plays a positive role in protecting neural tissues from demyelination.

Recent advances in optical imaging techniques have made it possible to monitor neural activity and provided powerful tools to reveal the spatiotemporal patterns of neural activity. We used optical imaging to determine whether nerve injury affects excitability of the sensory cortex. Male Sprague-Dawley rats were subjected to neuropathic surgery consisting of a tight ligation and transection of the left tibial and sural nerves while under pentobarbital anesthesia. The rats were reanesthetized with urethane two weeks post-operatively, and the exposed cortex surfaces were stained with a voltage-sensitive dye (di-2-ANEPEQ). After electrical stimulation of the receptive field, optical signals from the cerebral cortex were recorded using an optical imaging system. Increased optical intensity and an enlarged area of activation were observed in the cerebral cortex of neuropathic rats during electrical stimulation compared to normal or sham-operated rats. Higher electric stimulation resulted in more intensity and a larger area of activation in neuropathic rats. These results suggest that cortical excitability, resulting from peripheral stimulation, may be affected by nerve injury, which indicates a degree of neural plasticity.

We herein report a novel method of employing 254 nm of UV radiation (UV) for the modification of a polyethyleneimine (PEI) layer on silicone oxide film. In this study, a PEI layer composed of a 50 mM sodium carbonate solution (pH 8.2) was formed on the surface of a silicone oxide film with spontaneous adsorption. Then, thin film of PEI was patterned by UV radiation. To determine the effect of the UV radiation, fluorescence microscopy, X-ray electron spectroscopy (XPS), and Fourier Transform Infrared spectroscopy (FT-IR) analyses were performed. These results indicated that UV radiation could cause changes in the surface characteristics of the PEI layer. Subsequently, FT-IR analysis showed changes in the chemical composition of the PEI exposed to UV radiation, such as the disappearance of the amine. Based on these results, we can conclude that UV radiation could be used to eliminate the amine group selectively and that this technique could be applied to create a pattern on the surface of a PEI layer.

The molecular association of acceptors with electron donors is studied in the highly-polar solvent CH3CN. Tetracyanoquinodimethane (TCNQ) forms a stable charge-transfer complex with donor molecules such as 4aminobiphenyl (4-AB), benzidine (BD) and 2-aminobiphenyl (2-AB) with high association constants. The complexes of TCNQ with 4-AB or BD show new absorption bands at around 800 and 500 nm, which can be identified as reduced TCNQ − and TCNQ 2− species, respectively. These bands grow quickly upon photoirradiation, implying that the charge-transfer complexes are easily formed in an excited state. Conversely, a small spectral manifestation of the charge transfer was observed in the case of 2-AB complex. It is demonstrated that the structural orientation between the geminate ion pairs could play an important role in building a stable complex.

A high-efficiency voltage regulation stage in an energy harvesting system is presented. In an energy harvesting system, the availability of energy is uncertain. If energy is harvested from energy resources, the system operates; if not, the system does not work. Therefore, the energy harvesting system starts and stops repeatedly according to the presence or absence of energy. The repeated on and off state in the energy harvesting system decreases operating efficiency which is an important factor in such a system with the limited amount of harvested energy. To improve the efficiency of the system that repeatedly switch between on and off states, the energy dissipated in the transitional state should be minimized. In this work, a voltage regulation stage is implemented with two additional switches, two low power comparators and digital control logic in addition to the conventional regulation stage. The first switch determines the input voltage level of the regulation stage, and the second switch prevents undesired energy dissipation in the boosting state. When the regulation stage supplies power to a 100 ohm load resistor with a 100 uF load capacitor for 50 ms, the efficiency is improved up to 38%, and boosting time is reduced by 42% in comparison with the conventional regulation structure.

In the optical drive system adopting optical flying-type head (OFH), flying stability of small OFH interfaced with a removable plastic disk is investigated as basic functions of reliable optical pickup head for first surface recording. Additional micro actuators for focus servo are studied for better interface of OFH on the thin cover layered plastic disk to eliminate focus error due to the non-uniformity in cover layer thickness and the tolerance of lens assembly.

We performed nonlinear transmission measurements and quantum-chemical calculations on dithienothiophene (DTT)-based molecules to gain insight into the effect of acceptor and donor groups on two-photon absorption (TPA) properties. The TPA intensity showed dispersion characteristics of the single-photon absorption spectrum. When the molecules included an asymmetric donor-acceptor pair, the single- and two-photon absorption maximum wavelengths were red-shifted more than when the molecules had a symmetric donor-donor structure. We interpreted this result as indicating that the S 2 state plays the dominating role in the absorption process of molecules with a symmetric structure. The experimental TPA δ values at the absorption peak wavelength showed a dependence on the structural variations. We found the self-consistent force-field theory and Hartree-Fock Hamiltonian with single configuration interaction formalism to be valid for evaluating TPA δ. Although the quantum-chemical calculations slightly underestimated the experimental 8 values obtained from nonlinear transmission measurements, they reasonably predicted the dependence of the 8 value on the structural variations. We confirmed the role of molecular symmetry by observing that donor-donor substituted structure gave the highest experimental and theoretical TPA 8 values and that the donor-acceptor substituted structure showed a greater redshift in the TPA absorption maximum wavelength. Overall, the theoretical 8 values of DTT-based molecules were in the order of 10 -46 cm 4 .s.photon -1 and are higher than that of AF-50 by nearly two orders of magnitude.

In this study, we introduce a new design methodology of information granular-driven polynomial neural networks (IgPNNs) that is based on multi-layer perceptron with Context-based Polynomial Neurons (CPNs) or Polynomial Neurons (PNs). Our main objective is to develop a methodological design strategy of IgPNNs as follows: (a) The 1st layer of the proposed network consists of Context-based Polynomial Neuron (CPN). In here, CPN is fully reflective of the structure encountered in numeric data which are granulated with the aid of Context- based Fuzzy C-Means (C-FCM) clustering method. The context-based clustering supporting the design of information granules is completed in the space of the input data while the build of the clusters is guided by a collection of some predefined fuzzy sets defined in the output space. (b) The proposed design procedure being applied at each layer of IgPNN leads to the selection of preferred nodes of the network (CPNs or PNs) whose local characteristics can be easily adjusted. These options contribute to the flexibility as well as simplicity and compactness of the resulting architecture of the network. For the evaluation of performance of the proposed IgPNNs, we describe a detailed characteristic of the proposed model using a well-known learning machine data.

Emotions are complex processes involving multiple response channels, including physiological systems, facial expressions and voices. Bio-signals reflect sequences of neural activity, which result in changes in autonomic and neuroendocrine systems induced by emotional events. Therefore in human-computer interaction researches, one of the most current interesting topics in emotion recognition is to recognize human's feeling using bio-signals. The aim of this study is to classify emotions (joy, sadness, anger, fear, surprise, and neutral) that human have often experienced in real life from multichannel bio-signals using machine learning algorithms. We have measured physiological responses of three-hundred participants for acquisition of bio-signals such as electrodermal activity, electrocardiograph, skin temperature, and photoplethysmo-graph during six emotions induction. Also, for emotion classification, we have extracted eighteen features from the signals and performed emotion classification using four algorithms, linear discriminant analysis, Naive Bayes, classification and regression tree and support vector machine. The used algorithms were evaluated by only training, 10-fold cross-validation and repeated random sub-sampling validation. We have obtained recognition accuracy from 56.4 to 100% for only training and 39.2 to 53.9% for testing. Also, the result for testing showed that an accuracy of emotion recognition by Naive Bayes was highest (53.9%) and lowest by support vector machine (39.2%). This means that Naive Bayes is the best emotion recognition algorithm for basic emotions. This result can be helpful to provide the basis for the emotion recognition technique in human-computer interaction.

In this study, we introduce neural network recognizer based on fuzzy rules and fuzzy inference. The use of neural networks is proposed for efficient implementation of the fuzzy inference and the neural network is a trainable device consisting of some fuzzy rules and three processes, namely, premise, consequence and fuzzy inference processes. The premise process is driven by fuzzy c-means and the consequence processes deals with a polynomial function. A learning algorithm for the neural network recognizer is developed and its performance is compared with that of previous studies.

In this study, we introduce the development of hyperbox classifier with hierarchical two-level granular structure, namely set (interval) and fuzzy set in dealing with a description of geometry of patterns belonging to a certain category. We take advantage of the capabilities of sets when describing a core structure of classes of patterns in the form of some hyperboxes. Their combinations are referred to as a core structure of the feature space. Next, we refine the geometry of the classifier by bringing forward the concepts of regions of the feature space characterized by fuzzy sets. They are sought as a secondary structure. A series of numeric examples are used to demonstrate the effectiveness of the proposed classifiers.

This paper presents the results of mathematical analysis and simulation of broadcast channel bonding for transmitting massive UHD contents. Analysis and simulations have been performed to verify the performance of the channel bonding scheme in terms of allowable skew budget between bonded broadcast channels. When the data rate of UHD contents is fixed, the skew budget is independent of the number of bonded broadcast channels needed to transmit the contents. The skew budget is in inverse proportion to the data rate of UHD contents to be transmitted and the highest TS packet ratio having same PID value.

This study is related with emotion recognition based on autonomic nervous system responses. Three different emotional states, fear, surprise and stress, are evoked by stimuli and the autonomic nervous system responses for the induced emotions are measured as physiological signals such as skin temperature, electrodermal activity, electrocardiogram, and photoplethysmography. Twenty-eight features are analysed and extracted from these signals. The results of one-way ANOVA toward each parameter, there are significant differences among three emotions in some features. Therefore we select eight features from 28 features for emotion recognition. The comparative results of emotion recognition are discussed in view point of feature space with the selected features. For emotion recognition, we use four machine learning algorithms, namely, linear discriminant analysis, classification and regression tree, self-organizing map and naive bayes, and those are evaluated by only training, 10-fold cross-validation and repeated random sub-sampling validation. This can be helpful to provide the basis for the emotion recognition technique in human computer interaction as well as contribute to the standardization in emotion-specific ANS responses.

The N,N′-bis(ethyldihydrogen phosphate)-3,4,9,10-perylene(dicarboximide) (EPPI) have been well known as photoconducting materials in xerography and as photoinduced electron transporting materials. We describe its spectral properties in solution and self-assembled zirconium-EPPI multilayer on quartz substrate. Also, the orientation of EPPI molecules, the intermolecular interactions between EPPI molecules and layer formation was interpreted.

We have calculated TPA cross section Δ value of dithienothiophene (DDT)-based molecules to gain insight into the origin of the large δ values. The energy and transition dipole moments for the ground state and multiple excited states were calculated by combining the Hartree-Fock Hamiltonian with single configuration interaction formalism. For the calculation of the imaginary part of the third-order polarizability the sum-over-state expression was used. There are some differences between theoretical and experimental values. However the theoretical calculation reasonably estimates the δ values of the DTT-based molecules roughly 2–10 times larger than those fluorene- as well as stilbene-based ones.

We have fabricated spin valve ring shape sensors for the detection of micrometer size magnetic beads. By using a ring shape spin valve sensors, we were able to detect the presence of 2.8 mum size magnetic beads by direct measurement of magnetic dipole fields from the magnetic beads. The abrupt transition position of ring sensor transfer curves was changed from the 5 Oe to -10 Oe due to the presence of the 12 magnetic beads. It was also found that the sensitivities of ring sensors without and with magnetic beads were obtained about 0.11 mV/Oe and 0.08 mV/Oe, respectively. Variations of the abrupt transition position and maximum output signal were explained by the magnetic bead stray field effect. Our results shows that ring shape spin valve magnetic sensors are promising for the detection of biomolecules with magnetic labels.

The influence of the chain conformation on the formation of polymeric supramolecular complexes as well as the influence of the complexation on the conformation of the polymer chain has been studied. The complexation of pyrene into the cavity of β-cyclodextrin (β-CD) was investigated in aqueous solutions of β-CD substituted poly(allylamine) (PAA) under variation of external parameters, i.e. temperature, pH, ionic strength and addition of urea. The observed changes of the complexation constant K for the formation of the 2:1 β-CD/pyrene complex can be explained by a change of the chain flexibility which leads to a variation of the mean distance between neighbouring β-CD-moieties along the polymer chain. The intra-chain association of the decyl group with β-CD in PAA with co-pendant decyl and β-CD is disrupted by the addition of 1-adamantanamine HCI resulting in a more extended structure of the polymer. The β-CD moiety in PAA-CD shows one order of magnitude greater affinity to 2-(p-toluidyl)naphthalene-6-sulfonate than the native β-CD and the affinity increases further by the presence of decyl side groups.

The complexation of pyrene into the cavity of β-cyclodextrin (β-CD) has been studied in aqueous solutions of pure β-CD and β-CD substituted poly(allylamine) by using fluorescence spectroscopy. Two different approaches to obtain the association constant, both already described in the literature, are compared. It is shown that the evaluation of the fluorescence intensities of the first and third vibronic band of the pyrene fluorescence spectrum gives the correct result because the different quantum yields of free and complexed pyrene are considered correctly. The sole analysis of the Ham effect of pyrene leads to too high values of the association constant. A subsequent formation of 1:1 and 2:1 complexes between β-CD and pyrene was confirmed. The synthesized β-CD polymers exhibit a significant change in the complexation behavior depending on the degree of substitution (DS). At high DS (up to 23%) only 2:1 complex formation was observed, an evidence for intramolecular, chelate-like complexes due to the high ...

The polymerization of acrylamide in an inverse microemulsion has been studied by time resolved fluorescence measurements. The reaction was initiated by thermal and by photochemical decomposition of the initiator AIBN. A decrease of the fluorescence lifetime of the probe molecule pyrenetetrasulfonic acid sodium salt was observed. In case of the photochemically initiated reaction two distinct lifetimes could be separated. The corresponding pre-exponential factors showed a good correlation with the gravimetrically obtained conversion. During the thermally initiated polymerization the fluorescence decays as well as the intensity of the scattered light were measured on-line and analyzed by a mono-exponential decay law.

This paper proposes a technology to improve a sound recognition in real-world. The main issue is the change of spectrum which is caused by acoustic devices. The process through research and logical experiment is leads to two solutions which is mono speaker and acoustic path modeling by the rerecording.

In this paper, we present a multiplication table game that automatically detects and recognizes handwritten digits written on the white board. The result of the multiplication of two numbers would not only be displayed on the monitor, but it would be also spoken by the Text To Speech (TTS). The proposed application is divided into three stages: 1) detect a white board; 2) segment candidate regions of handwritten characters on the white board; 3) recognition using SVMs. In the experiment, the MNIST database of handwritten digits is used to evaluate the performance of the proposed application and very promising results are achieved.

In this paper, we propose an ellipsoidal face model-based image registration method to generate realistic facial textures. The suggested algorithm registers multiple 2D face images captured in different views with size-variable block matching that reflects both left-and-right and up-and-down face curvatures. For accurate block matching, the algorithm simultaneously considers color and texture features. It then employs weighting factor-based mosaiking and ghosting artifact elimination techniques to generate natural facial textures from registered images. Experimental results are given to demonstrate that the suggested ellipsoidal face model-based image registration algorithm can perform more effectively than other conventional approaches.

We have developed a novel platform for selective binding of magnetic labels on planar Hall resistance sensor (PHR) for biosensing applications. The photoresist (PR) micro wells were prepared on the PHR sensor junctions to trap the magnetic bead at specified locations on the sensor surface and thin layer of Au was sputtered in the PR wells immobilize bimolecular. The Au surface is functionalized with single-stranded oligonucleotide and further biotin was used to immobilize streptavidin coated magnetic labels (Dynabeads Myone 1.0 microm, Invitrogen Co.). After removal of the PR wells on the sensor surface the non specific binding magnetic labels were successfully removed and only the chemically bounded magnetic labels were remained on the Au surface for detection of biomolecules using PHR sensor. We controlled the number of magnetic labels on the PHR sensor surface by using different sizes of the PR well on the junctions. The specifically bounded magnetic labels were successfully detected by characterizing the individual PHR sensor junctions. This technique enables the complete control over the magnetic labels for selective binding of biomolecules on the sensor surface for increasing the sensitivity of the PHR sensor as well as removal of the non specific bindings on the sensor surface.

We describe photopatterning technique that employs the photodegradation of cell-adhesive-modified poly(ethyleneimine) (m-PEI) to fabricate precise micropatterns on the indium tin oxide (ITO) substrate for guided neuronal growth. The photodegradation of m-PEI coated on hydroxyl group-terminated ITO substrate created micropatterns over a large area through deep UV irradiation. The photopatterned m-PEI layer can effectively guide neurite outgrowth and control neurite extensions from individual neurons.

The fluorescence emission properties of 2-(2'-hydroxy-4'-R-phenyl)benzothiazole (HBT-R) nanoparticles with different substituents (R = -COOH, -H, -CH(3), -OH, and -OCH(3)) were investigated using spectroscopic and theoretical methods. HBT-Rs displayed dual enol and keto (excited-state intramolecular proton transfer (ESIPT)) emissions in nonpolar solvents. The spectral change of their ESIPT emissions was affected differently by the electron donating (or withdrawing) power of the substituents; a bathochromic shift for the electron donating group and a hypsochromic shift in electron withdrawing group. In addition, the changes in energy levels calculated by the ab initio method were consistent with the spectral shifts of HBT-R in solution. We prepared aggregated HBT-R nanoparticles using a simple reprecipitation process in tetrahydrofuran-water solvents. The ESIPT emission of aggregated HBT-R nanoparticles was strongly enhanced (over 45 times) compared to those of monomer HBT-Rs in toluene, as markedly shifted ESIPT emissions are observed at longer wavelength without any quenching by self-absorption. Aggregated HBT-R nanoparticles showed longer lifetimes than those of monomer molecules. The temperature effect on the aqueous dispersion of the aggregated HBT-R nanoparticles was also explored. It shows a fluorescent ratiometric change in a range of temperature from 7 to 65 degrees C. A mechanism of a temperature-dependent equilibrium between the nanoparticles and the solvated enols is proposed for the emission color change.

FK506 has been originally classified as an immunosuppressant and is known to exhibit neurotrophic actions in vitro and protective effects on some neurological conditions. We investigated the neuroprotective effects of FK506 on kainic acid (KA)-induced neuronal death in organotypic hippocampal slice cultures (OHSCs). After an 18 h KA (5 microM) treatment, significantly neuronal death was detected in the CA3 region using propidium iodide staining. However, neuronal death was significantly prevented at 24 and 48 h after treatment with 0.1 microM FK506. Using cresyl violet staining, we also observed that an increased number of CA3 neurons survived in the 0.1 microM FK506 group compared to the KA only group. Based on the results of the Western blot analysis, the expressions of 5-lipoxygenase and caspase-3 were reduced 24h after 0.1 microM FK506 treatment. The levels of superoxide dismutase (SOD) and phospho-Akt expression were increased by treatment with 0.1 microM FK506. These results suggest that FK506 may have a positive role in protecting neurons against cell death in the KA injury model of OHSCs.

In order to improve the efficiency of infection of primary human endothelial cells in vitro of Kaposi's sarcoma-associated herpesvirus (KSHV), the effect of low speed centrifugation was investigated. The recombinant KSHV, BAC36, was used to examine the centrifugal enhancement of KSHV. Infectivity was estimated by green fluorescent protein (GFP) expression and real-time RT-PCR. The enhancement of infectivity was dependent upon the time and force of centrifugation in human umbilical vein endothelial cells (HUVECs). Centrifugation enhanced the infectivity of KSHV by up to 70 fold compared to non-centrifugal control infection for the same period of time; viral mRNA expression was also enhanced by centrifugation. HUVECs that were centrifuged before infection with KSHV displayed no enhancement in infectivity; therefore, enhancement is believed to occur during centrifugation. In addition, the mechanisms of infection including the initial viral attachment to cells, lipid rafts, and clathrin-mediated and caveolae endocytosis appear to be similar in KSHV infection with and without centrifugal enhancement. These results show that low speed centrifugation could be a useful tool for improving the efficiency of KSHV infection in vitro.

We have demonstrated the use of highly sensitive spin valve sensors for the detection of micron magnetic beads. By using a ring type, cross type, and meander line type sensors, we were able to detect the presence of 2.8 μm size magnetic beads in real time by direct measurement of magnetic dipole fields from magnetic beads. The sensitivity of the ring, cross and meander line sensors were obtained about 50 μV/Oe, 7 μV/Oe, 30 μV/Oe and sensor output signals of 50 μV , 30 μV, 90 μV were obtained in an external applied field of 10 Oe and 1 mA sense current. Our results shows that ring, cross, and meander line shape spin valve sensors are very promising candidates for the detection of biomolecules with magnetic labels.

Objective. Nanoporous gold (Au) structures can reduce the impedance and enhance the charge injection capability of multi-electrode arrays (MEAs) used for interfacing neuronal networks. Even though there are various nanoporous Au preparation techniques, fabrication of MEA based on low-cost electro-codeposition of Ag:Au has not been performed. In this work, we have modified a Au MEA via the electro-codeposition of Ag:Au alloy, followed by the chemical etching of Ag, and report on the in vitro extracellular recording and stimulation performance of the nanoporous Au-modified MEA. Approach. Ag:Au alloy was electro-codeposited on a bilayer lift-off resist sputter-deposition passivated Au MEA followed by chemical etching of Ag to form a porous Au structure. Main results. The porous Au structure was analyzed by scanning electron microscopy and tunneling electron microscopy and found to have an interconnected nanoporous Au structure. The impedance value of the nanoporous Au-modified MEA is 15.4 ± 0.55 kΩ at 1 kHz, accompanied by the base noise V rms of 2.4 ± 0.3 μV. The charge injection limit of the nanoporous Au-modified electrode estimated from voltage transient measurement is approximately 1 mC cm−2, which is comparable to roughened platinum and carbon nanotube electrodes. The charge injection capability of the nanoporous Au-modified MEA was confirmed by observing stimulus-induced spikes at above 0.2 V. The nanoporous Au-modified MEA showed mechanical durability upon ultrasonic treatment for up to an hour. Significance. Electro-codeposition of Ag:Au alloy combined with chemical etching Ag is a low-cost process for fabricating nanoporous Au-modified MEA suitable for establishing the stimulus–response relationship of cultured neuronal networks.

We report a bi-layer lift-off resist (LOR) technique in combination with sputter deposition of silicon dioxide (SiO2) as a new passivation method in the fabrication of a multi-electrode array (MEA). Using the photo-insensitive LOR as a sacrificial bottom layer and the negative photoresist as a patterning top layer, and performing low-temperature sputter deposition of SiO2?followed by lift-off, we could successfully fabricate damage-free indium-tin oxide (ITO) and Au MEA. The bi-layer LOR sputter deposition processed Au MEA showed an impedance value of 6???105?? (at 1?kHz), with good consistency over 60 electrodes. The passivation performance of the bi-layer LOR sputter-deposited SiO2?was tested by electrodepositing Au nanoparticles (NPs) on the Au electrode, resulting in the well-confined and uniformly coated Au NPs. The bi-layer LOR sputter deposition processed ITO, Au, and Au NP-modified MEAs were evaluated and found to have a neuronal spike recording capability at a single unit level, confirming the validity of the bi-layer LOR sputter deposition as an effective passivation technique in fabrication of a MEA. These results suggest that the damage-free Au MEA fabricated with bi-layer LOR sputter deposition would be a viable platform for screening surface modification techniques that are available in neuronal interfacing.

In this paper, we demonstrated a facile photopatterning method that uses photocrosslinkable polyfluorene to fabricate micro-sized photopatterns on transparent indium tin oxide substrate for neuronal patterning. The modified poly(ethyleneimine) (m-PEI) with trimethoxysilane moiety was chemically attached to the hydroxyl group-terminated ITO surface and then the photopatternable polyfluorene derivative was spin coated as a cell-repellent layer onto the m-PEI-coated surface. The well-defined micropatterns were easily created over an entire surface by photocrosslinking of bromoalkyl-substituted polyfluorene (Br-PF) via the radical coupling reaction of a C–Br bond under UV irradiation without an initiator. UV-Vis absorbance, photoluminescence, ATR-FTIR and X-ray photoelectron spectroscopy were used to confirm the photocrosslinking process and the surface composition before and after the photocrosslinking of polyfluorene. The pairing of adhesive m-PEI and repulsive Br-PF effectively guided the neurite outgrowth and controlled neurite extension from individual neurons to the pre-patterned direction with excellent pattern fidelity. Guided neuronal cells were maintained for at least 25 days in vitro without any detachment of neuronal cells during cell culture. A photopatternable polyfluorene derivative in combination with cell-adhesive m-PEI is proved to be an effective way to modify the electrode surface to achieve single cell level neuronal networks.