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Ohlmeyer H.,Mittelhessen University of Applied Sciences | Ohlmeyer H.,TransMIT GmbH | Tobisch T.,TransMIT GmbH | Voncken M.M.A.J.,ASML B.V. | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Silica-based multimode fibers with a step-index refractive-index profile are commonly used for light transportation from 185 nm (DUV) up to 2300nm (NIR). Core diameters of such mono fibers range from 100 to 600 μm and their clad-tocore- ratios (CCR) typically are 1.1 and larger. If bundles are required for applications in the UV- and VIS-region, fibers with smaller core diameter and thinner cladding thicknesses are desired to reduce coupling losses, as their light acceptance surface area is then relatively larger. However, using these bundles at higher wavelengths, e.g. in the NIR-region, change of light-guiding properties can be observed. In fiber-optic light delivery systems, the transmission including light acceptance and guidance can be described by the concept of pupil apodization. However in fiber characterization, the numerical aperture (NA) of specialty fibers is an useful key parameter, which will be determined using the inverse far-field method at two separate laser wavelengths with focused light excitation. With parallel light, skew rays/modes must be taken into account. In addition, the spectral fiber attenuation with Uniform Mode Distribution (UMD) illumination and mode-selective illumination will be discussed and compared with experimental NA results. As expected, the ratio of cladding thickness and wavelength is the most important parameter on the light-guiding properties in short-length applications with increasing wavelength. © 2014 Copyright SPIE.


Tu C.,Florida College | Scafa N.,World Precision Instruments Inc. | Zhang X.,World Precision Instruments Inc. | Silverman D.N.,Florida College
Electroanalysis | Year: 2010

The NO electrode and membrane inlet mass spectrometry (MIMS) have the advantage of being sensitive, direct, and real time detectors of NO in aqueous solution. They do not require reacting NO with labels or purging of NO with an inert gas. We show that the NO electrode and MIMS are comparable in sensitivity detecting NO concentrations to 0.5 nM in aqueous solution, and both give identical results in a biological measurement, the reactions of deoxyhemoglobin with nitrite.


Zimmer A.W.,Mittelhessen University of Applied Sciences | Raithel P.,Mittelhessen University of Applied Sciences | Raithel P.,TransMIT GmbH | Belz M.,World Precision Instruments Inc. | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

A novel experimental set-up for measuring the spectral dependency of light-guidance of specialty non-active multimodefibers will be introduced. Light coupling into the test fiber is realized and controlled with a micro-structured single mode (SM) fiber and an image-system based on a microscope objective The far-and near-field profiles of the SM-fiber will be shown. The inverse far field method is modified and improved by using three wavelengths simultaneously under the same input conditions; the coupling conditions into the test-fiber and the far-and near-field at fiber output are observed with cameras. The numerical aperture (NA) and mode-conversion or focal-ratio-degradation (FRD) are measured in respect to wavelength at three wavelengths in the VIS region. For the analysis, the patterns are captured at varying exposure times to increase the dynamic range and finally analyzed using image processing methods. Characteristic parameters, such as skew mode propagation and ray-conversion, of circular and non-circular MM-fibers will be discussed, taking the surface roughness into account. © 2016 SPIE.


Werner J.,TransMIT GmbH | Belz M.,World Precision Instruments Inc. | Klein K.-F.,Mittelhessen University of Applied Sciences
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2015

Optical key parameter of fiber optic flow cells for absorbance measurements are transmission and numerical aperture. In this work we introduce an experimental setup to determine the far field intensity profile of flow cells at different wavelengths in the UV and visible part of the light spectrum. Comparison to spectral transmission will be shown, too. © 2015 SPIE.


Heimann J.,TransMIT GmbH | Raithel P.,TransMIT GmbH | Raithel P.,Mittelhessen University of Applied Sciences | Tobisch T.,TransMIT GmbH | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Step-index multimode fibers with non-circular core are becoming popular and offer several interesting new light-guiding properties, which can be studied with an emphasis on selective modes or ray patterns. Observing the far-field profile at the fiber output, ray-conversion can be determined, taking the azimuthal angle defined in respect to an adjusted reference into account. Using the inverse far-field method at one laser wavelength, the numerical aperture (NA) of these specialty fibers is determined as a function of excitation condition, such as input angle and rotation around the fiber axis. Further angledependent analysis of ring-shaped far-field pattern at the fiber output resulted in significant differences between the fibers with non-circular core shapes and claßic circular fibers. In addition, with squared core fibers, the near-and farfield pattern at their respective fiber output were varying due to rotating the fiber around the fiber axis at their input side. Especially, a disturbance of the azimuthally homogenous ring shape was observed using input angles close to the numerical aperture of the fiber. © 2015 COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.


Xu T.,University of Science and Technology Beijing | Scafa N.,World Precision Instruments Inc. | Xu L.-P.,University of Science and Technology Beijing | Su L.,University of Science and Technology Beijing | And 5 more authors.
Electroanalysis | Year: 2014

Nitric oxide (NO) plays an important role in physiological processes and it has been confirmed some human diseases are related to its biological function. Electrochemical sensors provide an efficient way to explore the NO function in biological processes. This review details different kinds of electrochemical sensors used for NO concentration detection between 2008 and 2013 together with their application in biological samples. Four commonly used electrodes and different assisted analysis membranes used for contributions towards the development of the novel sensors were summarized. Electrochemical sensors employed to measure NO concentration in a single cell, cell culture, tissue homogenate, organ, in vivo, human being, as well as in plant were also detailed. The trends of developing novel NO sensors were outlooked in the last part. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Patent
World Precision Instruments Inc. | Date: 2011-04-07

A light emitting diode (LED) based detection system is employed for spectroscopy based applications. LEDs are used as monochromatic light sources for applications at specific and pre-defined wavelengths. Spectrographic information is generated using LEDs of different wavelengths ranging from 260 nm to 1400 nm. Multiple wavelength information is generated by coupling light from each LED into an intensity and mode mixing fiber bundle. A dual beam approach of using a reference and a sample photodiode ensures automatic drift correction. Interference filters at the LED input fiber reduce the spectral bandwidth of the monochromatic light emission to a useful 10 nm bandwidth by cutting off the LEDs trailing emission distribution allowing for absorbance measurements similar to typical spectrometers.


Patent
World Precision Instruments Inc. | Date: 2010-09-28

A method of rapidly and accurately identifying and analyzing thiol proteins in a sample using gold nanoparticles. Disclosed are embodiments of a flow device for isolation, fractionation and subsequent instrumental analysis of thiol containing proteins from various samples or tissue sources using gold nanoparticles. Also disclosed are embodiments of a flow device for detecting, isolating and fractionating S-nitrosated proteins and peptides for subsequent analysis, including identification of S-nitrosation sites.


The scientific characterization of cellular contractility and cell movement, such as muscle function in particular is, to a large extent, carried out on intact tissue preparations for example using whole intact muscles from animals. Typical indices of muscle function may include isometric force, contractility under external force (load) and spatio-temporal determination of internal calcium concentration under strictly controlled conditions of length and applied force. The major advance of the described apparatus is that the common characterization of cellular contractility can be performed on a single cell rather than an entire tissue or whole animal. As such the apparatus described improves on and eliminates known limitations of currently considered state-of-the-art approaches.


Patent
World Precision Instruments Inc. | Date: 2011-12-07

An electrochemical sensor for measurement of hydrogen sulfide is described. The electrochemical sensor comprises an electrolyte; an electrolyte container comprising a hydrogen sulfide permeable membrane; a working electrode and a reference electrode both disposed in the electrolyte; and an instrument capable of maintaining a fixed DC potential in the range of 0 mV to 1,000 mV between the working electrode and the reference electrode. Also a method of detecting hydrogen sulfide in a sample. The method comprises providing an electrochemical sensor; at least partially immersing the gas permeable membrane in the sample; and detecting hydrogen sulfide in the sample. The detection may be qualitative or quantitative.

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