Active Q control may be used to modify the effective quality (Q) factor of an atomic force microscope (AFM) micro-cantilever when operating in tapping mode. The control system uses velocity feedback to obtain an effective cantilever Q factor to achieve optimal scan speed and image resolution for the imaging environment and sample type. Time delay of the cantilever displacement signal is the mos...

We present quantitative and qualitative detection of analyte vapors using a microfabricated silicon cantilever array. To observe transduction of physical and chemical processes into nanomechanical motion of the cantilever, swelling of a polymer layer on the cantilever is monitored during exposure to the analyte. This motion is tracked by a beam-deflection technique using a time multiplexing sch...

We report a microarray of cantilevers to detect multiple unlabeled biomolecules simultaneously at nanomolar concentrations within minutes. Ligand-receptor binding interactions such as DNA hybridization or protein recognition occurring on microfabricated silicon cantilevers generate nanomechanical bending, which is detected optically in situ. Differential measurements including reference cantile...

The frequency response of a cantilever beam is strongly dependent on the fluid in which it is immersed. In a companion study, Sader @J. Appl. Phys. 84, 64, ~1998!# presented a theoretical model for the flexural vibrational response of a cantilever beam, that is immersed in a viscous fluid, and excited by an arbitrary driving force. Due to its relevance to applications of the atomic force micros...

In atomic force microscopy (AFM) a sharp cantilever tip is used to scan surfaces at the atomic level. One further application is force spectroscopy, in which force-distance curves between binding partners located on the cantilever and substrate surface are determined. This requires specifically immobilized molecules. Herein we describe the covalent binding of single adenosine and thymidine nucl...

The frequency-resolved viscoelasticity of a hydration layer on a mica surface was studied by pulse-response measurement of a magnetically driven atomic force microscopy cantilever. Resonant ringing of the cantilever due to its 1st and 2nd resonance modes was suppressed by means of the Q-control technique. The Fourier-Laplace transform of the deflection signal of the cantilever gave the frequenc...

We show that a microfabricated field-effect sensor located at the terminus of a freestanding cantilever can detect surface potential changes resulting from the adsorption of charged molecules in an aqueous environment. The charge sensitive region, defined by lightly doped silicon, is embedded within the heavily doped silicon cantilever. Since both the electrical trace and sensitive region are p...

OBJECTIVE The aim of this study was to analyze whether or not a cantilever extension on a fixed dental prosthesis (FDP) supported by implants increased the amount of peri-implant bone loss or technical complications compared with reconstructions without cantilevers. MATERIALS AND METHODS Fifty-four partially dentate patients with a total of 54 FDPs supported by 78 implants were enrolled in th...

In this article we examine four objections to the genetic modification of human beings: the freedom argument, the giftedness argument, the authenticity argument, and the uniqueness argument. We then demonstrate that each of these arguments against genetic modification assumes a strong version of genetic determinism. Since these strong deterministic assumptions are false, the arguments against g...