56 research outputs found
Cantilever Based Optical Interfacial Force Microscope
We developed a cantilever based optical interfacial force microscopy (COIFM) that employs a microactuated silicon cantilever and optical detection method to establish the measurement of the single molecular interactions using the force feedback technique. Through the direct measurement of the COIFM force-distance curves, we have demonstrated that the COIFM is capable of unveiling structural and mechanical information on interfacial water at the single molecular level over all distances between two hydrophilic surfaces
A parametric symmetry breaking transducer
Force detectors rely on resonators to transduce forces into a readable
signal. Usually these resonators operate in the linear regime and their signal
appears amidst a competing background comprising thermal or quantum
fluctuations as well as readout noise. Here, we demonstrate that a parametric
symmetry breaking transduction leads to a novel and robust nonlinear force
detection in the presence of noise. The force signal is encoded in the
frequency at which the system jumps between two phase states which are
inherently protected against phase noise. Consequently, the transduction
effectively decouples from readout noise channels. For a controlled
demonstration of the method, we experiment with a macroscopic doubly-clamped
string. Our method provides a promising new paradigm for high-precision force
detection.Comment: 7 pages, 5 figure
Cantilever-Based Optical Interfacial Force Microscopy
Atomic force microscopy (AFM) is one of the most important tools that lead current nanoscience and nanotechnology in many diverse areas including physics, chemistry, material engineering, and nano-biology. The current AFM technique has been routinely applied to forced unbinding processes of biomolecular complexes such as antibody-antigen binding, ligand-receptor pairs, protein unfolding, DNA unbinding, and RNA unfolding studies (Butt et al., 2005; Fritz & Anselmetti, 1997; Schumakovitch et al., 2002). AFMs have also been applied to intermolecular friction studies (Carpick et al., 1997; Colchero et al., 1996; Fernandez-Torres et al., 2003; Goddenhenrich et al., 1994; Goertz et al., 2007; B.I. Kim et al., 2001; Major et al., 2006). These previous techniques of measuring friction employed a lateral modulation of the sample relative to the cantilever as a means to measure normal force and friction force at the same time (Burns et al., 1999a; Carpick et al., 1997; Colchero et al., 1996; Goddenhenrich et al., 1994; Goertz et al., 2007; Major et al., 2006)
Filter-free exhaustive odds ratio-based genome-wide interaction approach pinpoints evidence for interaction in the HLA region in psoriasis
Solid State NMR Spectroscopy a Valuable Technique for Structural Insights of Advanced Thin Film Materials: A Review
Solid-state NMR has proven to be a versatile technique for studying the chemical structure, 3D structure and dynamics of all sorts of chemical compounds. In nanotechnology and particularly in thin films, the study of chemical modification, molecular packing, end chain motion, distance determination and solvent-matrix interactions is essential for controlling the final product properties and applications. Despite its atomic-level research capabilities and recent technical advancements, solid-state NMR is still lacking behind other spectroscopic techniques in the field of thin films due to the underestimation of NMR capabilities, availability, great variety of nuclei and pulse sequences, lack of sensitivity for quadrupole nuclei and time-consuming experiments. This article will comprehensively and critically review the work done by solid-state NMR on different types of thin films and the most advanced NMR strategies, which are beyond conventional, and the hardware design used to overcome the technical issues in thin-film research
Detection of HTTPS brute-force attacks in high-speed computer networks
Tato práce pĹ™edstavuje pĹ™ehled metod pro detekci sĂĹĄovĂ˝ch hrozeb se zaměřenĂm na Ăştoky hrubou silou proti webovĂ˝m aplikacĂm, jako jsou WordPress a Joomla. Byl vytvoĹ™en novĂ˝ dataset, kterĂ˝ se skládá z provozu zachycenĂ©ho na páteĹ™nĂ sĂti a ĂştokĹŻ generovanĂ˝ch pomocĂ open-source nástrojĹŻ. Práce pĹ™inášà novou metodu pro detekci Ăştoku hrubou silou, která je zaloĹľena na charakteristikách jednotlivĂ˝ch paketĹŻ a pouĹľĂvá modernĂ metody strojovĂ©ho uÄŤenĂ. Metoda funguje s šifrovanou HTTPS komunikacĂ, a to bez nutnosti dešifrovánĂ jednotlivĂ˝ch paketĹŻ. Stále vĂce webovĂ˝ch aplikacĂ pouĹľĂvá HTTPS pro zabezpeÄŤenĂ komunikace, a proto je nezbytnĂ© aktualizovat detekÄŤnĂ metody, aby byla zachována základnĂ viditelnost do sĂĹĄovĂ©ho provozu.This thesis presents a review of flow-based network threat detection, with the focus on brute-force attacks against popular web applications, such as WordPress and Joomla. A new dataset was created that consists of benign backbone network traffic and brute-force attacks generated with open-source attack tools. The thesis proposes a method for brute-force attack detection that is based on packet-level characteristics and uses modern machine-learning models. Also, it works with encrypted HTTPS traffic, even without decrypting the payload. More and more network traffic is being encrypted, and it is crucial to update our intrusion detection methods to maintain at least some level of network visibility
- …