5697 results about "Shear force" patented technology

Optical films formed by deposition of highly oriented nanowires and methods of aligning suspended nanowires in a desired direction by flow-induced shear force are described.

A cardiopulmonary bypass system utilizing membrane-based reciprocating positive displacement blood pumps (“pod pumps”). In one aspect, the pod pumps are constructed to provide reduced shear forces on the blood being pumped. In another aspect blood flow through the pod pumps can be controlled by a controller using information from pressure sensors in the control chamber of the pod pumps. In another aspect, the pod pumps are included on a disposable unit that can be received and held by a receptacle means on a base unit, the base unit also providing pressurized control fluid to the pod pumps on the disposable unit through the receptacle means.

To conduct a fluid, the transducer has a flow tube which in operation vibrated by an excitation assembly. Inlet-side and outlet-side vibrations of the flow tube are sensed by means of a sensor arrangement. To produce shear forces in the fluid, the flow tube is at least intermittently excited into torsional vibrations about a longitudinal flow-tube axis. An internal portion of the transducer, formed at least by the flow tube, an antivibrator, the sensor arrangement, and the excitation assembly and mounted at least on the inlet and outlet tube sections, has a centroid which is located inside the flow tube. The transducer is suitable for use in viscometers or Coriolis mass flowmeter-viscometers. In spite of using only a single straight flow tube, it is dynamically well balanced in operation, and the development of bending moments by the torsionally vibrating flow tube is largely prevented. This also effectively prevents the transducer case or the connected pipe from being excited into sympathetic vibration. Measurement signals representative of mass flow rate are readily distinguishable from measurement signals representative of viscosity, particularly if the sensors used for the viscosity measurement are also used for the mass flow measurement.

The present invention provides structures and methods that allow polymers of any length, including nucleic acids containing entire genomes, to be stretched into a long, linear conformation for further analysis. The present invention also provides structures and methods for selecting and stretching polymers based on their lengths. Polymers are loaded into a device and run through the structures. Stretching is achieved by, e.g., applying shear forces as the polymer passes through the structures, placing obstacles in the path of the polymer, or a combination thereof. Since multiple molecules may be stretched in succession, extremely high throughput screening, e.g., screening of more than one molecule per second, is achieved.

A tubular tissue scaffold is described which comprises a tube having a wall, wherein the wall includes biopolymer fibrils that are aligned in a helical pattern around the longitudinal axis of the tube where the pitch of the helical pattern changes with the radial position in the tube wall. The scaffold is capable of directing the morphological pattern of attached and growing cells to form a helical pattern around the tube walls. Additionally, an apparatus for producing such a tubular tissue scaffold is disclosed, the apparatus comprising a biopolymer gel dispersion feed pump that is operably connected to a tube-forming device having an exit port, where the tube-forming device is capable of producing a tube from the gel dispersion while providing an angular shear force across the wall of the tube, and a liquid bath located to receive the tubular tissue scaffold from the tube-forming device. A method for producing the tubular tissue scaffolds is also disclosed. Also, artificial tissue comprising living cells attached to a tubular tissue scaffold as described herein is disclosed. Methods for using the artificial tissue are also disclosed.

A method for forming monodisperse lipoplex assemblies includes providing a microfluidic device having a main microfluidic channel coupled to first and second reactant inlet channels. The first inlet channel is used to deliver a cationic lipid to the main channel while the second channel is used to deliver a nucleic acid. A droplet generation zone is provided in the main channel at the intersection of first and second carrier channels that contain a hydrophobic fluid. The cationic lipid, nucleic acid, and the hydrophobic fluid are then pumped through the device. In the droplet generation zone, shear force from the hydrophobic fluid pinches off droplets. The cationic lipid and nucleic acid are mixed in the generated droplets as the droplets move within a mixing region. A plurality of splitting channels may be coupled to the outlet of the device to produce smaller, monodisperse droplets having picoliter volumes.

Compositions and methods in which dry-committed fibers are substantially homogeneously dispersed throughout a fibrous composition. The fibrous composition is characterized as having sufficient yield stress and viscosity such that the shearing forces from the mixing apparatus are effectively transferred down to the fiber level. This is accomplished by means of an appropriate thickening agent, e.g, gelatinized starch. The dry-committed fibers are exemplified by flash dry fibers or fibrous sheets that have been cut or torn into fragments less than 2 cm across. Providing fibers that have been dry-committed greatly reduces the time that it takes to obtain substantially homogeneous dispersion of the fibers throughout the fibrous composition. This, in turn, reduces the risk of mixture spoilage and mechanical or chemical damage to the solid components within the fibrous composition.

An adjustable-height bicycle seat post assembly comprises a hollow seat post for supporting a bicycle seat slidably on plastic guides or shims inside a hollow tube. The hollow tube clamps into the frame of a bicycle. A mainspring forces the post upward, but a locking mechanism interconnects the post with the tube in various fixed positions relative to the tube. The locking mechanism includes a housing, which supports a plunger for reciprocating movement into and out of engagement with holes on the post. The locking mechanism is affixed to the outside of the tube to bear shearing forces on the plunger. An endcap on the locking mechanism and a topcap on the tube protect the assembly from foreign debris. The locking mechanism may be manipulated remotely using a magnetic switch assembly or manually using a mechanical assembly. A lost motion coupling is integrated into the locking mechanism and/or actuator assembly to enable the remote actuator to be moved or deployed while the latch remains trapped under the influence of a dominant shear load. The lost motion coupling is also effective to allow an operator to deploy the remote actuator at any convenient time prior to a desired change in seat height.

An adjustable height bicycle seat post assembly comprises a hollow seat post for supporting a bicycle seat slidably supported on plastic shims inside a hollow tube. The hollow tube clamps into the frame of a bicycle. A main spring forces the post upward, but a locking mechanism interconnects the post with the tube in various fixed positions relative to the tube. The locking mechanism includes a foundation and a projection extending from the foundation having a counterbore for guiding a plunger into holes on the post. The locking mechanism adheres to the outside of the tube to bear shearing forces on the plunger. An endcap on the locking mechanism and a top cap on the tube protect the assembly from foreign debris. The locking mechanism may be manipulated remotely using a magnetic switch assembly or manually using a manual assembly.

In an aspect, a medication delivering injector which includes a housing having opposing proximal and distal ends and an accessible internal cavity for inserting and removing a medicament container such as a syringe. The injector is designed to hold and manipulate a medication delivery device such as a large variety of standard and non-standard medical syringes with fixed or attached needles, assembled such that centrally located is a cylinder containing a liquid medicament and attached either permanently or removably to the distal end of the cylinder, is a hypodermic needle or cannula in fluidic communication with the cylinder. The needle can be from one-half inches to one-and-one-half inches in length in the illustrated embodiment and other sizes are possible by changes in scale of the injector. At the proximal end of the cylinder is an opening with an inserted seal or bung with an attached rod thus constituting a plunger. The central medicament containing cylinder could also be a standard medicament cartridge. Hereinafter, both are referred to as a “syringe”. A lid or access cover which, in an open position permits insertion and removal of the syringe into/from the housing in a horizontal fashion thus providing ease of loading. The syringe is inserted with the needle end toward the distal end of the housing and the plunger toward the proximal end of the housing. A movable carriage is disposed in the proximal end of the housing and slides in the axial direction forwards and rearwards such that a syringe, whose proximal end is gripped by the carriage, so moves with the carriage such that the needle exits the housing at the distal end of the housing and pierces the tissue of the patient prior to dispensing of the medicament, and then is retracted after the medicament has been dispensed by retraction of the carriage. Attached to the carriage is an actuator which pushes on the syringe plunger causing the medicament contained within the syringe cylinder to be dispensed through the needle into the patient's tissue. In one embodiment suitable for both removable needle and fixed needle syringes, the proximal end of the syringe including the syringe finger flange is gripped by an elastomeric flange grip which resides within the carriage, while the syringe distal end resides in and is supported by a “syringe guide” which is attached to the carriage and thus moved with it. In another embodiment which is so made to accommodate syringes with removable needles and their safe disposal, the syringe flange at the proximal end of the cylinder is gripped by an elastomeric flange grip which resides in the carriage as described above, while the syringe distal end is supported by a needle which resides in a removable disposable needle shield. The needle guide is biased toward the carriage and thus, the syringe body is compressed and guided as the carriage moves forward and rearward.

Both the movement of the carriage and the actuator are controlled by servo motors which are controlled by electronics and a microcontroller so operating such that speeds and accelerations are controlled smoothly and gently so as to avoid the stop/start motion of motors controlled by limit switches and simple electronics or the vibration and abruptness such as result from injectors powered by compressed springs or gas. Furthermore, the forces are adaptive to the loads imposed and the requirements necessary for the proper dispensation of medicaments with high viscosity or sensitivity to shear forces.

The housing, approximately midway between proximal and distal ends, is affixed by a hinge such that the device can be folded in half to provide for a more compact device to be stored and transported.

On the distal end of the housing are electrical sensor pads in communication with the microcontroller such that contact with the patient's skin and the angle at which the injector is held against the skin and the steadiness with which the injector is being held can be ascertained. Within the housing are a haptic vibrator and an audio speaker, both producing a vibration which is variable in pitch in such a manner that biofeedback is provided to the injector user as to the pressure, angle and steadiness with which they are holding the injector against the skin. This facilitates the action of injection oneself in the gluteus muscle where visual feedback isn't available to the patient.

Multiplexed onto the electrical sensor pads, is a TENS (Transcutaneous Electrical Nerve Stimulation) generator which is operational (at the user's choice) just before and during the injection to interrupt or quench the pain of tissue perforation often accompanied with needle injections.

Contained on the surface of the housing such as on the access cover, is a display such that user menus, device state, directions, and battery charge status, etc. are displayed. Also contained on the surface of the housing, on the proximal half, are buttons which control the menus and selections that are shown on the display. These selections provide for the user to set such parameters as hypodermic insertion speed and medicament dispensing speeds, the preferred mode of user biofeedback which can include: speech mode (which can be accompanied by musical themes and ringtones, plus variable pitch tone and haptic vibration), MP3 mode (which has speech muted but includes musical ringtones and variable pitch tone and haptic vibration), and haptic mode (which is haptic vibration and audio tone queues needed for injector position biofeedback and readiness), plus mute mode (which provides no audio but the haptic vibration remains), and none, which provides no vibrational biofeedback, yet the display information always remains available.

Also contained on the surface of the housing on the distal half, is an “injection initiate” button which causes the sequences required for performance of an injection to occur if said button is “enabled”.

Contained within the electronics and its operating program is the ability to audibly play pre-recorded human speech in any language such that: directions in the form of consecutive steps which are required to load the medicament container (syringe) into the device, consecutive steps to perform an injection, steps to remove and properly dispose of parts, to alert of device status and menu choices, etc. can be played through the audio speaker. Also contained within the electronics and program is the ability to play musical ringtones as a distraction during the needle insertion and injection or when a scheduled injection alarm is reached, or calming human voice exhibiting bedside manner during the needle insertion and injection.

Also contained within the electronics and software is a real-time clock-calendar which can store a patient's injection schedule and play a musical ringtone as an alarm as each scheduled injection becomes due. Also contained within the electronics and software are the ability to communicate with a personal computer through a USB port, which can also charge the injector's rechargeable battery. The battery in one embodiment, consists of three AAA batteries which can be rechargeable or non-rechargeable. The USB port in combination with an application running on the personal computer, is used to download the injection schedule into the real-time clock-calendar and to download ringtones and musical themes of the user's choice and to download foreign language sets for the pre-recorded human language feature.

The injector can be further equipped with the capability to aspirate the tissue by drawing back on the plunger thus creating a vacuum into which fluids will flow. These fluids enter the syringe cylinder where they can be checked for the presence of blood by optical absorption in the red spectrum. This information is useful in the instances where intramuscular injections are to be given with drugs whose ‘Full Prescribing Information’ instructs the patient to aspirate and check for blood in the syringe which indicates that the puncture of a vein has occurred, and if so detected, to abort the injection and then re-inject into a different location.

The present invention relates to a method and a device for transporting a molecule through a mammalian barrier membrane of at least one layer of cells comprising the steps of: ablating said membrane with a shear device; and utilizing a driving force to move said molecule through said perforated membrane.

The invention discloses an exciting device for testing dynamic property of an MEMS microstructure or micro-device and belongs to a minitype mechanical electronic system. A structure of the device comprises that: a microstructure to be tested is arranged on a crossed spring strip of the top part; the crossed spring strip is arranged on the top part of a sleeve by a bolt; piezoelectric ceramics, an upper connecting block, a steel ball, a lower connecting block and a pressure sensor are arranged inside the sleeve; the bottom of the piezoelectric ceramics is fixed on the upper connecting block; the top part is contacted with the crossed spring strip to change the thickness of an adjustable washer; the piezoelectric ceramics is pressed by the crossed spring strip; the pressure sensor is arranged on a base plate; and the base plate and the sleeve are connected by a bolt. The exciting device has the advantages that in normal environment the device can carry out excitation on the MEMS microstructure, can remove shearing force produced in the using process of the piezoelectric ceramics and effectively prolong the service life of the piezoelectric ceramics through exertion of certain pretightening force on the piezoelectric ceramics at the same time; and the device can measure the output force of the piezoelectric ceramics by the pressure sensor, thereby conveniently seeking a frequency response function of the microstructure and obtaining dynamic property parameters of the microstructure.

A stent delivery system deploys a stent having an inner periphery that defines an interior space extending lengthwise along at least a part of the stent and comprising at least one segment having relatively low column strength. The stent delivery system comprises a stabilizer which is disposed within the stent interior space and has a surface element adapted to engage the stent inner periphery in a region containing the low-column-strength segment. The surface element may comprise a sleeve or a coating having a high friction surface adapted to transmit adequate shear force to the stent to move the stent relative to the outer sheath upon deployment. Alternatively, or in addition, the surface element can include at least one radial protuberance. The protuberances may comprise rings of various cross-sections, axial lengths, or space sizes therebetween, or may be in the form of discrete barbs, bumps, or inflatable knobs arranged in a ringed configuration or helical pattern about the stabilizer. The stabilizer may also comprise an inner core and a heat-moldable compression sleeve surrounding the inner core, the heat-moldable compression sleeve having an outer surface comprising a plurality of protuberances defined by a thermal imprint of the stent inner periphery on the compression sleeve outer surface. A method for delivering a stent using a stent delivery system as described herein is also disclosed, as is a method for loading a stent and stabilizer having a heat-moldable compression sleeve into a stent delivery system.

Methods and devices are disclosed for treating the vertebral column. An integrated fixation plate and spacer having a retaining structure within the screw holes of the fixation plate to resist backout of screws attaching the fixation plate to the bone is provided. A movable joint may be provided between the fixation plate and spacer. In some embodiments, a screw hole insert is also provided to resist shear forces acting between the screw and fixation plate. In some embodiments, an integrated fixation plate and spacer system is provided, comprising two or more integrated fixation plate and spacer implants, wherein the fixation plates of each implant has a complementary configuration to allow attachment of the implants at adjacent intervertebral spaces. Alternative fixation systems are also contemplated.