Our Experience
The goal of the scientific instrument developer is to provide the user with the
means to achieve ever greater contrast. If one instrument can separate a spectral
peak from the noise where a rival cannot, it clearly has better contrast. Similarly,
if one microscope can distinguish between two features, it has greater contrast
than one that blurs them together. The aim of the software designer is to produce
a product that is efficient, effective, engaging, error tolerant and easy to learn.
With many years of development experience, Sevensoft have expertise in:
IR spectroscopy is a powerful technique for the chemical analysis of many compounds
through the measurement of optical absorption bands. Fourier transform IR spectroscopy
is usually prefered over the older dispersive technique, because it offers better
speed and signal to noise. Key techniques of an FTIR instrument are low noise electronics
, low distortion electronics
, bandwidth narrowing ,
and high performance electromechanical actuators.
Sevensoft have also been involved in the development of FTIR spectromenters which
use multiprocessors to perform the
fourier transform and thermal control
loops to achieve high instrument stability.
Ultraviolet-visible spectroscopy or ultraviolet-visible spectrophotometry (UV/ VIS) involves the spectroscopy of photons and spectrophotometry. It uses light in the visible and adjacent near ultraviolet (UV) and near infrared (NIR) ranges. In this region of energy space molecules undergo electronic transitions.
Gas chromatography (GC) is a type of chromatography in which the mobile phase is a carrier gas, usually an inert gas such as helium, nitrogen or hydrogen and the stationary phase is a microscopic layer of liquid or polymer on an inert solid support, inside glass or metal tubing, called a column. The instrument to perform gas chromatographic separations is called a gas chromatograph
GC/IR is a combined technique of using GC to separate components then identify them
with FTIR. It is an efficient tool for analyzing complex mixtures.
The key feature of confocal microscopy is its ability to produce blur-free images of thick specimens at various depths. Images are taken point-by-point and reconstructed with a computer, rather than projected through an eyepiece. The principle for this special kind of microscopy was developed by Marvin Minsky in 1953, but it took another thirty years and the development of lasers for confocal microscopy to become a standard technique toward the end of the 1980s.
Two-photon excitation microscopy is a fluorescence imaging technique that allows imaging living tissue up to a depth of one millimeter. The two-photon excitation microscope is a special variant of the multiphoton fluorescence microscope. Two-photon excitation may in some cases be a viable alternative to confocal microscopy due to its deeper tissue penetration and reduced phototoxicity
The most commonly used fluorophores have excitation spectra in the 400–500 nm range, whereas the laser used to excite the fluorophores lies in the ~700–1000 nm (infrared) range. If the fluorophore absorbs two infrared photons simultaneously, it will absorb enough energy to be raised into the excited state. The fluorophore will then emit a single photon with a wavelength that depends on the type of fluorophore used (typically in the visible spectrum). Because two photons need to be absorbed to excite a fluorophore, the probability of emission is related to the intensity squared of the excitation beam. Therefore, much more two-photon fluorescence is generated where the laser beam is tightly focused than where it is more diffuse. Effectively, fluorescence is observed in any appreciable amount in the focal volume, resulting in a high degree of rejection of out-of-focus objects. The fluorescence from the sample is then collected by a high-sensitivity detector, such as a photomultiplier tube. This observed light intensity becomes one pixel in the eventual image; the focal point is scanned throughout a desired region of the sample to form all the pixels of the image.
The use of infrared light to excite fluorophores in light-scattering tissue has added benefits. Longer wavelengths are scattered to a lesser degree than shorter ones, which is a benefit to high-resolution imaging. In addition, these lower-energy photons are less likely to cause damage outside of the focal volume. There are several caveats to using two-photon microscopy: Pulsed lasers are generally much more expensive, the microscope requires special optics to withstand the intense pulses, the two-photon absorption spectrum of a molecule may vary significantly from its one-photon counterpart, and wavelengths greater than 1400 nm may be significantly absorbed by the water in living tissue.
Laser Capture Microdissection is a method for procuring pure cells from specific microscopic regions of tissue sections. Under the microscope, tissues are heterogeneous complicated structures with hundreds of different cell types locked in morphologic units exhibiting strong adhesive interactions with adjacent cells, connective stroma, blood vessels, glandular and muscle components, adipose cells, and inflammatory or immune cells. In normal or developing organs, specific cells express different genes and undergo complex molecular changes both in response to internal control signals, signals from adjacent cells, and humoral stimuli. In disease pathologies, the diseased cells of interest, such as precancerous cells or invading groups of cancer cells, are surrounded by these heterogeneous tissue elements. Cell types undergoing similar molecular changes, such as those thought to be most definitive of the disease progression, may constitute less than 5% of the volume of the tissue biopsy sample. Therefore, microdissection is essential to apply molecular analysis methods to study evolving disease lesions in actual tissue. The microdissected cDNA libraries are designed to approximate the true pattern of gene expression of the pure cell subpopulations in their actual tissue context.
Flow cytometry is a technique for counting, examining and sorting microscopic particles suspended in a stream of fluid. It allows simultaneous multiparametric analysis of the physical and/or chemical characteristics of single cells flowing through an optical and/or electronic detection apparatus.
X-ray fluorescence (XRF) is the emission of characteristic "secondary" (or fluorescent) X-rays from a material that has been excited by bombarding with high-energy X-rays or gamma rays. The phenomenon is widely used for chemical analysis, particularly in the investigation of metals, glass, ceramics and building materials, and for research in geochemistry, forensic science and archaeology.
Polarimetry can be used to measure various optical properties of a material, including linear birefringence, circular birefringence (also known as optical rotation or optical rotary dispersion), linear dichroism, circular dichroism and scattering.
To measure these various properties, there have been many designs of polarimeters. The most sensitive polarimeters are based on interferometers, while more conventional polarimeters are based on arrangements of polarising filters, wave plates or other devices.
Raman spectroscopy is a spectroscopic technique used in condensed matter physics and chemistry to study vibrational, rotational, and other low-frequency modes in a system. It relies on inelastic scattering, or Raman scattering of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range. The laser light interacts with phonons or other excitations in the system, resulting in the energy of the laser photons being shifted up or down. The shift in energy gives information about the phonon modes in the system. Infrared spectroscopy yields similar, but complementary information.
Typically, a sample is illuminated with a laser beam. Light from the illuminated spot is collected with a lens and sent through a monochromator. Wavelengths close to the laser line (due to elastic Rayleigh scattering) are filtered out and those in a certain spectral window away from the laser line are dispersed onto a detector.