다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label-free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label-free impedance biosensors and identify areas for future research.

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Label-Free Impedance Biosensors: Opportunities and Challenges.

Foreword. Series Editor's Foreword. Preface. 1. Liquid crystal physics.* Introduction.* Thermodynamics and statistic physics.* Orientational order.* Elastic properties of liquid crystals.* Response of liquid crystals to electro-magnetic fields.* Anchoring effects of nematic liquid crystal at surfaces. 2. Propagation of light in anisotropic optical medium.* Electromagnetic wave.* Polarization.* Propagation of light in uniform anisotropic optical media.* Propagation of light in cholesteric liquid crystals. 3. Optical modeling methods.* Jones matrix method.* Mueller matrix method.* Berreman 4x4 method. 4. Effects of Electric field on Liquid Crystals.* Dielectric interaction.* Flexoelectric Effect.* Ferroelectricity in liquid crystals. 5. Freedericksz transition.* Calculus of variation.* The Fredeericksz transition: statics.* The Freedericksz transition: dynamics. 6. Liquid Crystal Materials.* Introduction.* Refractive indices.* Dielectric constants.* Rotational Viscosity.* Elastic constant.* Figure-of-merits.* Refractive index matching between liquid crystals and polymers. 7. Modeling of liquid crystal director configuration.* Electric energy of liquid crystals.* Modeling electric field.* Simulation of liquid crystal director configuration. 8. Transmissive liquid crystal display.* Introduction.* Twisted nematic cells.* In plane switching (IPS) mode.* Vertical alignment (VA) mode.* Multi-domain Vertical Alignment (MVA) Cells.* Optically compensated bend (OCB) cell. 9. Reflective and Trasreflective display.* Introduction.* Reflective liquid crystal displays.* Transflector.* Classification of Transflective LCDs.* Dual-cell-gap Transflective LCDs.* Single-cell-gap Transflective LCDs.* Performance of transflective LCDs. 10. Liquid crystal display matrices, drive schemes and bistable displays.* Segmented displays.* Passive matrix displays and drive scheme.* Active Matrix Displays.* Bistable ferroelectric liquid crystal displays and drive scheme.* Bistable nematic displays.* Bistable cholesteric reflective display. 11. Liquid crystal/polymer composites. * Introduction.* Phase separation.* Scattering properties of liquid crystal/polymer composites.* Polymer dispersed liquid crystals.* Polymer stabilization liquid crystals.* Displays from liquid crystal/polymer composites. 12. Tunable liquid crystal photonic devices. * Introduction.* Laser beam steering.* Variable Optical Attenuators.* Tunable-Focus Lens.* Polarization-Independent LC Devices. Index.

Fundamentals of Liquid Crystal Devices

As their name indicates, liquid crystals simultaneously exhibit some characteristics common to both ordinary isotropic liquids and solid crystals. This ambivalence is also found in the effects of surfaces on these systems which lead to a great diversity of phenomena. These phenomena are reviewed focusing on nematic liquid crystals which have the simplest structure among the many existing types and which have been the most extensively studied. Three main kinds of effects can be distinguished. The first concerns the perturbation of the liquid crystalline structure close to the surface. Beyond this transition region, the bulk liquid crystalline structure is recovered with an orientation which is fixed by the surface: this phenomenon of orientation of liquid crystals by surfaces is the so-called anchoring. Finally, close to bulk phase transitions, critical adsorption or wetting can occur at surfaces as is also seen in isotropic systems.

https://iopscience.iop.org/article/10.1088/0034-4885/54/3/002/pdf

Surface effects and anchoring in liquid crystals

Engineering biocompatible implant surfaces

Variational calculus theory of elasticity 1 - fundamentals theory of elasticity II - applications molecular models subsurface deformations in nematics.

An Elementary Course on the Continuum Theory for Nematic Liquid Crystals

NEMATIC LIQUID CRYSTALS: FUNDAMENTALS AND BULK PROPERTIES Nematic Order Parameters Maier-Saupe Approach for the Nematic-Isotropic Phase Transition Continuum Description of the Nematic Phase External Field Contribution to the Elastic Energy Density Equilbrium Configuration in Strong and Weak Anchoring Situations NEMATIC LIQUID CRYSTALS: SURFACE PROPERTIES Anchoring The Anchoring Energy Function Periodic Deformations in Nematic Liquid Crystals Spontaneous Periodic Distortions in Nematic Liquid Crystals: Dependence on the Tilt Angle Theoretical Models for the Surface Free Energy Stochastic Contribution to the Anchoring Energy: Deviation from the Rapini-Papolar Expression Validity of the Elastic Model for Nematic Surface Anchoring Energy Contribution of the Smectic-Nematic to the Surface Energy TEMPERATURE DEPENDENCE OF THE SURFACE FREE ENERGY Thermal Relaxation Model of Surface Director Gliding in Lyotropic Liquid Crystals Thermal Renormalization of the Anchoring Energy Temperature Induced Surface Transition in Nematic Liquid Crystals Oriented by Evaporated SiOx A Local Self-Consistent Approach to the Phase Transition at the Nematic Liquid Crystal - Wall Interface SURFACE ADSORPTION OF PARTICLES: GENERAL CHARACTERISTICS Introduction Statement of the Problem: Langmuir's Isotherm Surface Adsorption and Anchoring Transition Photo-Manipulation of the Anchoring Strength of Photochromic Nematic Liquid Crystal Adsorption of Magnetic Grains in Magnetic Fluids Selective Ionic Adsorption in Liquid Crystals SURFACE ELECTRIC FIELD-INDUCED INSTABILITIES IN NEMATIC LIQUID CRYSTALS SAMPLE The General Electrostatic Model Analysis I: Variation Solution of the Eigenvalue Problem Analysis II: Series Solution of the Eigenvalue Problem Role of the Elastic Term Linear in the Spatial Derivatives of the Nematic Director in a 1D Geometry Conclusions IONS AND NEMATIC SURFACE ENERGY: BEYOND THE EXPONENTIAL APPROXIMATION FOR THE ELECTRIC FIELD OF IONIC ORIGIN Introduction Theoretical Model: Non-Linear Poisson-Boltzman Equation External Electric Field Effect in the Nematic Anchoring Energy Contribution to the Surface Energy of Dielectric Origin Conclusions ADSORPTION PHENOMENON AND EXTERNAL FIELD EFFECT ON AN ISOTROPIC LIQUID CONTAINING IMPURITIES Introduction The Model The Charge and Field Distributions Ionic Adsorption in the Absence of External Equilibrium Distribution of Charges Extensions of the Model Influence of the Adsorption Energy in the Dieletric Contribution to the Anchoring Energy FERMILIKE DESCRIPTION OF THE ADSORPTION PHENOMENON Introduction The Fermi-Like Model Application: Ion Adsorption in Isotropic Fluids Limits Numerical Results Conclusions

Adsorption Phenomena and Anchoring Energy in Nematic Liquid Crystals

We investigate the role of the diffuse layer of the ionic cloud on impedance spectroscopy measurements. The analysis is performed assuming that the ions have equal mobility, the electrodes are perfectly blocking and adsorption phenomenon can be neglected. We find that the dielectric permittivity, in the limit of high frequency ω, tends to the dielectric permittivity of the pure liquid as ω−3/2. The relationship between the detected equivalent permittivity and conductivity of the cell with the real and imaginary part of the complex dielectric constant is discussed. We show also that the presence of the ions is responsible for a distribution of relaxation times. An application to nematic liquid crystals is presented.

Role of the diffuse layer of the ionic charge on the impedance spectroscopy of a cell of liquid

We investigate, theoretically, for what amplitude of the applied voltage to an electrolytic cell the concept of impedance is meaningful. The analysis is performed by means of a continuum model, by assuming the electrodes perfectly blocking. We show that, in the low-frequency range, the electrolytic cell behaves as a linear system only if the amplitude of the measurement voltage is small with respect to the thermal voltage VT=kBT∕q, where kBT is the thermal energy, and q is the modulus of the electrical charge of the ions, assumed identical except for the sign of the charge. On the contrary, for large frequency, we prove that the amplitude of the applied signal has to be small with respect to a critical voltage that is frequency dependent. The same kind of analysis is presented for the case in which the diffusion coefficients of the positive ions is different from that for negative ions, and for the case where surface adsorption takes place.

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Significance of small voltage in impedance spectroscopy measurements on electrolytic cells

Recent reports have claimed that the simple Rapini-Papoular form for the anchoring energy of nematic liquid crystals is not correct for large distortions. We show that, taking into account the dielectric energy associated with the flexoelectric effect, a reanalysis of the data is consistent with the Rapini-Papoular form. The consideration of flexoelectricity is necessary in most practical cases where the Debye screening length of the material compares to (or is larger than) the surface anchoring energy extrapolation length. Close to the nematic-isotropic transition, another dielectric effect, related to the order-electricity, must also be considered. This effect can justify the functional form proposed in order to interpret the experimental data giving the surface torque vs. tilt angle near the nematic isotropic transition.

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Giovanni Barbero

Papers

An Elementary Course on the Continuum Theory for Nematic Liquid Crystals

Adsorption Phenomena and Anchoring Energy in Nematic Liquid Crystals

Role of the diffuse layer of the ionic charge on the impedance spectroscopy of a cell of liquid

Significance of small voltage in impedance spectroscopy measurements on electrolytic cells

On the validity of the Rapini-Papoular surface anchoring energy form in nematic liquid crystals