Search results for "techniques"
showing 10 items of 4426 documents
Plasmonics co-integrated with silicon nitride photonics for high-sensitivity interferometric biosensing
2019
We demonstrate a photonic integrated Mach-Zehnder interferometric sensor, utilizing a plasmonic stripe waveguide in the sensing branch and a photonic variable optical attenuator and a phase shifter in the reference arm to optimize the interferometer operation. The plasmonic sensor is used to detect changes in the refractive index of the surrounding medium exploiting the accumulated phase change of the propagating Surface-Plasmon-Polariton (SPP) mode that is fully exposed in an aqueous buffer solution. The variable optical attenuation stage is incorporated in the reference Si3N4 branch, as the means to counter-balance the optical losses introduced by the plasmonic branch and optimize interfe…
Optical Quality Comparison of Conventional and Hole-Visian Implantable Collamer Lens at Different Degrees of Decentering
2012
To compare the optical quality of implantable Collamer lens (ICL) with and without central hole (Hole ICL and conventional ICL) at different degrees of decentering.Experimental laboratory investigation.Wavefront aberrations of the -3, -6, and -12 diopter (D) V4b and -3, -6, and -12 D V4c ICLs were measured in 3 conditions-centered and decentered 0.3 and 0.6 mm-at 3-mm and 4.5-mm pupils. The root mean square of total higher order aberrations, trefoil, coma, tetrafoil, secondary astigmatism, and spherical aberration were evaluated. In addition, point spread function and simulated retinal images of ICLs were calculated from the wavefront aberrations for each ICL and all conditions of decenteri…
Birth of the Localized Surface Plasmon Resonance in Monolayer-Protected Gold Nanoclusters
2013
Gold nanoclusters protected by a thiolate monolayer (MPC) are widely studied for their potential applications in site-specific bioconjugate labeling, sensing, drug delivery, and molecular electronics. Several MPCs with 1-2 nm metal cores are currently known to have a well-defined molecular structure, and they serve as an important link between molecularly dispersed gold and colloidal gold to understand the size-dependent electronic and optical properties. Here, we show by using an ab initio method together with atomistic models for experimentally observed thiolate-stabilized gold clusters how collective electronic excitations change when the gold core of the MPC grows from 1.5 to 2.0 nm. A …
On the Theoretical Limits of Noise-Gain-Mismatch Tradeoff in the Design of Multi-Stage Cascaded Transistor Amplifiers
2007
The problem of evaluating the limit performances of cascaded single-ended multi-stage transistor amplifiers is addressed. In particular, a theoretically rigorous approach is proposed for the determination of a family of optimal design curves (ODC's) which express the best (maximum optimal) noise-gain tradeoff that can be achieved - at each operating frequency - when a simultaneous constraint on amplifier input VSWR is accounted for.
A gradient-based decomposition approach to optimize pressure path and counterpunch action in Y-shaped tube hydroforming operations
2008
International audience; In tube hydroforming, the concurrent actions of pressurized fluid and mechanical feeding allows obtaining tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. Main process parameters are material feeding history (i.e., the punches velocity history), internal pressure path during the process, and (in T- or Y-shaped tube hydroforming) counterpunch action. What is crucial, in such processes, is the proper design of operative parameters aimed to avoid defects (for instance underfilling or ductile fractures). Actually, the design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence …
Analytical Approach Determining the Optimal Length of Paired Drip Laterals in Uniformly Sloped Fields
2015
Microirrigation plants, if properly designed, allow for water use efficiency to be optimized and high values of emission uniformity to be obtained in the field. Disposing paired laterals, for which two distribution pipes extend in opposite directions from a common manifold, can contribute to reducing the initial investment cost that represents a limiting factor for small-scale farmers of developing countries where in the last decade, the diffusion of such irrigation systems has been increasing. The objective of this paper is to propose an analytical approach to evaluate the maximum lengths of paired drip laterals for any uniform ground slope, respecting the criteria to maintain emitter flow…
A promising camptothecin derivative: Semisynthesis, antitumor activity and intestinal permeability.
2014
Oral administration of camptothecin (Cm) derivatives and other antitumoral agents is being actively developed in order to improve the quality of life of patients with cancer. Though several lipophilic derivatives of CPT have shown interesting oral bioavailability in preclinical and clinical studies, only Topotecan has been approved for this route of administration. Semisynthesis, antitumor activity, biological inhibition mechanism, and in situ intestinal permeability of 9, 10-[1,3]-Dioxinocamptothecin (CDiox), an unexplored CPT derivative, have been studied in this paper. The hexacyclic analog was as effective as Topotecan and CPT in different tumor cell lines, showing an expected similar a…
Precision-cut liver slices: A tool to model the liver ex vivo
2013
D is ea se Precision-cut liver slices: A tool to model the liver ex vivo Peter Olinga1,2,*, Detlef Schuppan2 1Division of Pharmaceutical Technology and Biopharmacy, Departement of Pharmacy, University of Groningen, The Netherlands; 2Molecular and Translational Medicine, Department of Medicine I, University Medical Center, Johannes Gutenberg University Mainz, Germany *Corresponding author. Address: Division of Pharmaceutical Technology and Biopharmacy, Departement of Pharmacy, University of Groningen, The Netherlands. Tel.: + 31 50 363 8373; fax: +31 50 363 2500. *E-mail address: P.Olinga@rug.nl
Surgical time for graft preparation using different suture techniques
2016
Background: The purpose of the present study was to compare the operative time for graft prepa- ration using different techniques for graft sutur- ing. Material and methods: Flexor profundus tendons were harvested from fresh pig hind-leg trotters. Three different suture techniques were investigat- ed: the Krackow stitch (K), the Whipstitch (W), and the Modified Finger-Trap suture (MFT). Ten- dons were sutured starting at 10 mm from the dis- tal free end of the tendon. The suture configura- tions of the Krackow stitch and Whipstitch were completed with five suture throws. According to the MFT technique, the suture was wrapped five times around the tendon over a distance of 30 mm. The time re…
The accuracy of the Raypex5 electronic apex locator using stainless-steel hand K-file versus nickel-titanium rotary Mtwo file
2009
Objectives: Today many clinicians use both stainless-steel hand K-files and nickel- titanium rotary files during endodontic treatment. It is of great importance for the clinician to have confidence in the accuracy of an apex locator even if these files were used interchangeably. The purpose of this in-vitro study was to evaluate the accuracy of the Raypex5 electronic apex locator using stainless-steel hand K-file versus nickel-titanium rotary Mtwo file. Study design: Twenty straight and single canals of maxillary central teeth were used. Access cavities were prepared; actual working length were determined and compared with electronic working length obtained by means of apex locator Raypex5 …