Abstract: A cylindrical or annular polymeric bioreactor is disclosed which provides enhanced mixing and aeration of the growth medium while simultaneously offering reduced mechanical shear force.

Abstract: A method for precision thermal measurement and control, especially for bioreactors, as well as the correction of temperature sensitive probes such as pH and dissolved oxygen. Typical control requirements are +/?0.1° C. The thermal measurement circuit converts a sensor output to a high level voltage or current with great accuracy and provides noise immunity and sensor isolation. While digital outputs from sensor converters can have the greatest noise immunity, the noise associated with digital circuitry may contaminate low level sensor signals so in many cases an analog sensor converter is preferred because of low noise generation, especially if the converter is near the sensor. The circuit is low cost, reliable, generates minimal heat is immune to, and does not generate noise, and requires minimal calibration effort.

Abstract: A port for use with a bioreactor vessel comprising: i) a base member comprising a hollow tubular portion and a base plate configured to be sealingly affixed to a hole in the wall of a bioreactor vessel ii) a hollow, generally tubular bushing member for containing electrical, optical, microfluidic and/or chemical monitoring components which bushing member fits inside the bore of the tubular portion of the base member, both the base member and bushing member providing access to the contents of a bioreactor by; iii) a monitoring assembly inserted into the bushing member which assembly comprises means for providing incoming optical and/or electrical signals and means for collecting and transmitting measurement signals resulting from the interaction of incoming optical and/or electrical signals with the contents of a bioreactor; and iv) a cover which maintains the position and alignment of components ii) and iii) relative to the base member.

Abstract: A validation apparatus for testing the measurement accuracy of a phase fluorimeter comprising: i) a photodetector responsive to the excitation light emitted by a phase fluorimeter; ii) electronics connected to the detector which calculates the phase of the light emitted by the phase fluorimeter and causes a light source in the validation apparatus to emit light of a wave length which will stimulate the detector of the phase fluorimeter but which is phase shifted relative to the light emitted by the phase fluorimeter.

Abstract: A system and method for analyzing a target analyte gas concentration using a photoacoustic spectroscopy cell comprising: i) a modulatable light source which provides optical radiation at an absorption wavelength of a target analyte; ii) a resonant acoustic chamber for containing said analyte; iii) a microphone positioned within said chamber whereby the acoustic reactance of the microphone is a substantial factor in determining the acoustic resonant frequency of the acoustic chamber and where the magnitude of the acoustic reactance of the microphone is at least two times the acoustic resistance of the microphone.

Abstract: A validation apparatus for testing the measurement accuracy of a phase fluorimeter comprising: i) a photodetector responsive to the excitation light emitted by a phase fluorimeter; ii) electronics connected to the detector which calculates the phase of the light emitted by the phase fluorimeter and causes a light source in the validation apparatus to emit light of a wave length which will stimulate the detector of the phase fluorimeter but which is phase shifted relative to the light emitted by the phase fluorimeter.

Abstract: An optical loss probe utilized as a bioreactor process monitor manifesting a substantially linear response in optical loss vs. concentration of scatterers present in an aqueous medium in the range of between about 0 AU and about 4.0 AU, said probe comprising: i) a light source, ii) an optical detector, and iii) an optical gap between said light source and said optical detector, said optical detector having a receiving aperture configured such that the solid angle of acceptance of the light passing through said optical gap and impinging on said optical detector is less than ?/50 radians.

Abstract: A method for compensating for changes in output power or wavelength of an optical source with temperature. Many optical sources have power and/or wavelength variations with temperature which can be compensated by open- or closed-loop methods if a method of accurately measuring the optical source temperature is available. The voltage across a semiconductor junction varies with temperature. Measuring the optical source power or wavelength variation with temperature and tracking the voltage across the semiconductor junction provides a means for compensating an instrument for temperature induced optical output power or wavelength variations. An important field of application is optical density or turbidity measurements in cellular media.

Abstract: A method for analyzing a target analyte gas concentration using a photoacoustic spectroscopy cell comprising: i) a modulatable light source which provides optical radiation at an absorption wavelength of a target analyte; ii) a resonant acoustic chamber for containing said analyte; iii) a microphone positioned within said chamber whereby the acoustic reactance of the microphone is substantially equal but opposite in value to the acoustic reactance of the chamber at a selected cell resonance frequency.

Abstract: A port for use with a bioreactor vessel comprising: i) a base member comprising a hollow tubular portion and a base plate configured to be sealingly affixed to a hole in the wall of a bioreactor vessel ii) a hollow, generally tubular bushing member for containing electrical, optical, microfluidic and/or chemical monitoring components which bushing member fits inside the bore of the tubular portion of the base member, both the base member and bushing member providing access to the contents of a bioreactor by; iii) a monitoring assembly inserted into the bushing member which assembly comprises means for providing incoming optical and/or electrical signals and means for collecting and transmitting measurement signals resulting from the interaction of incoming optical and/or electrical signals with the contents of a bioreactor; and iv) a cover which maintains the position and alignment of components ii) and iii) relative to the base member.

Abstract: A circularizated semiconductor laser diode (CSLD), such as for example a vertical cavity surface emitting laser (VCSEL) may be used for optical measurements. The CSLD may be used in a cell density probe to perform cell density determination and/or turbidity determination, such as in a biotech, fermentation, or other optical absorbance application. The cell density probe may comprise a probe tip section made from a polytetrafluoroethylene material, which provides sealability, ease of manufacture, durability, cleanability, optical semi-transparency at visible and near infrared wavelengths, and other advantages. The probe tip advantageously provides an optical gap that allows for in situ measurements of optical measurements including but not limited to absorbance, scattering, and fluorescence.

Abstract: A method for analyzing gas concentration using doubly resonant photoacoustic spectroscopy, and a doubly resonant photaoacoustic gas detector comprising: i) a continuous wave light beam whose wavelength coincides with an absorption wavelength of a gaseous analyte; ii) a closed path optical cavity having at least two reflective surfaces; iii) an acoustic resonator chamber contained within said optical cavity, and comprising an acoustic sensor for detecting sound waves generated by a gaseous analyte present within said chamber, the light beam passing sequentially into, through and out of said chamber, and being repeatedly reflected back and forth through said chamber, and being modulated at a frequency which is equal to or equal to one-half of an acoustic resonance frequency of said acoustic resonator chamber.