摘要:
To sequence DNA automatically, DNA marked with far infrared, near infrared, or infrared fluorescent dyes are electrophoresed in a plurality of channels through a gel electrophoresis slab or capillary tubes wherein the DNA samples are resolved in accordance with the size of DNA fragments in the gel electrophoresis slab or capillary tubes into fluorescently marked DNA bands. The separated samples are scanned photoelectrically with a laser diode and a sensor, wherein the laser scans with scanning light at a wavelength within the absorbance spectrum of said fluorescently marked DNA samples and light is sensed at the emission wavelength of the marked DNA.
摘要:
To sequence DNA automatically, DNA marked with near infrared fluorescent dyes are electrophoresed in a plurality of channels through a gel electrophoresis slab wherein the DNA samples are resolved in accordance with the size of DNA fragments in the gel electrophoresis slab into fluorescently marked DNA bands. The separated samples are scanned photoelectrically with a laser diode and a sensor, wherein the laser scans with scanning light at a scanning light frequency within the absorbance spectrum of said fluorescently marked DNA samples and light is sensed at the emission frequency of the marked DNA. The light is modulated from said laser at a predetermined modulation frequency and fluorescent light emitted by said DNA bands at said modulation frequency is detected, whereby background noise from the medium through which the light is transmitted is discriminated against.
摘要:
To sequence DNA automatically, DNA marked with near infrared fluorescent dyes are electrophoresed in a plurality of channels through a gel electrophoresis slab wherein the DNA samples are resolved in accordance with the size of DNA fragments in the gel electrophoresis slab into fluorescently marked DNA bands. The separated samples are scanned photoelectrically with a laser diode and a sensor, wherein the laser scans with scanning light at a scanning light frequency within the absorbance spectrum of said fluorescently marked DNA samples and light is sensed at the emission frequency of the marked DNA. The light is modulated from said laser at a predetermined modulation frequency and fluorescent light emitted by said DNA bands at said modulation frequency is detected, whereby background noise from the medium through which the light is transmitted is discriminated against.
摘要:
To sequence DNA, DNA samples marked with flourscent infrared dye are applied at a plurality of locations for electrophoresing in a plurality of channels through a gel electrophoresis slab. The channels are scanned with a laser and a sensor, that include a microscope focused on the gel slab. The focal point and slab are adjusted with respect to each other so that the focal point of the microscope remains on the gel slab during a scan. The data from the scan is directly used to amplitude modulate density readings on a display, and the scan is displayed in a horizontal sweep of a cathode ray tube, whereby said cathode ray tube provides intensity displays of bands representing DNA. Different sizes of glass gel sandwiches may be mounted to the same console for different sequencing tasks.
摘要:
To permit a portable light meter to operate without zero adjustment and without excessive battery drain, a chopper-stabilized amplifier amplifies the DC signal from the light sensor of the light meter. The chopper in the chopper-stabilized amplifier is an FET circuit having a high impedance compensating circuit to avoid battery drain while compensating for interelectrode capacitance. The power supply obtains the ground level potential from the output of an operational amplifier with negative and positive potentials being generated from that reference potential so as to not require a center tap on the battery pack.
摘要:
To sequence long strands of DNA, cloned strands having lengths longer than 100 bases are, in one embodiment, marked on one end with biotin. These strands are divided into 4 aliquots and each aliquot: (1) is uniquely chemically treated to randomly terminate the strands at the non-biotinylated end at a selected type of base; and (2) is moved continuously by electrophoresis through a different one of four identical channels. In the one embodiment, the strands are randomly terminated at a selected base type and they are moved into avidin, which due to high affinity, combines with the biotin marked ends of shorter strands before the longer strands are fully resolved in the gel. The avidin is marked with fluorescein, the strands are scanned and the signals are decoded. In another embodiment, the strands are synthesized, with termination at a selected base type and marked either by the above method or by ethidium bromide.
摘要:
The resolution of the measuring system of a conveyor type leaf-area meter is optimized when changes are made in the size of the area that is scanned by adjusting: (1) the lens of the scanner; (2) the rate of readout of the pulses from the scanner; and (3) the decimal place of the display unit.
摘要:
To provide a printout corresponding to the integral of the current or voltage from any of several different instruments, a printing integrator includes a voltage-to-frequency converter which receives current or voltage through a replaceable buffer amplifier and provides pulses to a counter at a rate proportional to the amplitude of the input current or voltage. The output of the counter is printed in rows along with the time of printing and an indication of the state of the battery.To generate pulses at a rate proportional to an input signal, a charge is periodically supplied to a feedback capacitor of an operational amplifier from a storage capacitor in the voltage-to-frequency converter, and an input current derived from the signal decreases the charge in the feedback capacitor until the output potential of the operational amplifier drops below a level set on a comparator, thus generating a pulse and initiating another discharge from the storage capacitor into the feedback capacitor.
摘要:
To sequence DNA, DNA samples marked with fluorescent infrared dye are applied at a plurality of locations for electrophoresing in a plurality of channels through a gel electrophoresis slab. The channels are scanned with a laser and a sensor, that include a microscope focused on the gel slab. The focal point and slab are adjusted with respect to each other so that the focal point of the microscope remains on the gel slab during a scan. The data from the scan is directly used to amplitude modulate density readings on a display, and the scan is displayed in a horizontal sweep of a cathode ray tube, whereby said cathode ray tube provides intensity displays of bands representing DNA. Different sizes of glass gel sandwiches may be mounted to the same console for different sequencing tasks.
摘要:
An optical system is disclosed that can be used for fluorescence filtering for molecular imaging. In one preferred embodiment, a source subsystem is disclosed comprising a light source and a first set of filters designed to pass wavelengths of light in an absorption band of a fluorescent material. A detector subsystem is also disclosed comprising a light detector, imaging optics, a second set of filters designed to pass wavelengths of light in an emission band of the fluorescent material, and an aperture located at a front focal plane of the imaging optics. A telecentric space is created between the light detector and the imaging optics, such that axial rays from a plurality of field points emerge from the imaging optics parallel to each other and perpendicular to the second set of filters.