1952 results about "Transition temperature" patented technology

Spinal stabilization devices and their methods of insertion and use to treat degenerated lumbar, thoracic or cervical spinal discs in minimally invasive, outpatient procedures are described. In one embodiment, the spinal stabilization device is an expandable cage made of a coil or perforated cylindrical tube with a bulbous or bullet-shaped distal end and a flat or rounded proximal end. In a preferred embodiment, the spinal stabilization device is mechanically expanded to a larger diameter or is made of a superelastic nickel-titanium alloy which is thermally programmed to expand to a relatively larger diameter when a pre-determined transition temperature below body temperature is reached. To treat a degenerated disc, a guide wire is inserted into the disc and an endoscope is inserted through a posterolateral puncture in the back and advanced up to the facet of the spine. Mechanical tools or laser energy, under endoscopic visualization, are used to remove or vaporize a portion of the facet bone, creating an opening into the foraminal space in the spine for insertion of an endoscope, which enables the disc, vertebra and nerves to be seen. The passageway is expanded, mechanical tools or laser of RF energy are used to make a tunnel into the disc, and a delivery cannula is inserted up to the opening of the tunnel. An insertion tool is used to insert one or more spinal stabilization devices into the tunnel in the disc, preserving the mobility of the spine, while maintaining the proper space between the vertebra. Laser or radio frequency (RF) energy is used to coagulate bleeding, vaporize or remove debris and shrink the annulus of the disc to close, at least partially, the tunnel made in the disc.

A thermally-conductive interface for conductively cooling a heat-generating electronic component having an associated thermal dissipation member such as a heat sink. The interface is formed as a self-supporting layer of a thermally-conductive material which is form-stable at normal room temperature in a first phase and substantially conformable in a second phase to the interface surfaces of the electronic component and thermal dissipation member. The material has a transition temperature from the first phase to the second phase which is within the operating temperature range of the electronic component.

A phase change memory cell includes first and second electrodes having generally coplanar surfaces spaced apart by a gap and a phase change bridge electrically coupling the first and second electrodes. The phase change bridge may extend over the generally coplanar surfaces and across the gap. The phase change bridge has a higher transition temperature bridge portion and a lower transition temperature portion. The lower transition temperature portion comprises a phase change region which can be transitioned from generally crystalline to generally amorphous states at a lower temperature than the higher transition temperature portion. A method for making a phase change memory cell is also disclosed.

A phase change memory cell includes first and second electrodes electrically coupled by a phase change element. At least a section of the phase change element comprises a higher reset transition temperature portion and a lower reset transition temperature portion. The lower reset transition temperature portion comprises a phase change region which can be transitioned, by the passage of electrical current therethrough, from generally crystalline to generally amorphous states at a lower temperature than the higher reset transition temperature portion. The phase change element may comprise an outer, generally tubular, higher reset transition temperature portion surrounding an inner, lower reset transition temperature portion.

In order to ensure that a vehicle seat, having a supporting face and incorporating microcapsules of phase-change material having a phase transition temperature between 15 and 37° C., is comfortable to use in terms of temperature, the support face is heated or cooled before the seat is used so that the phase-change material is at its transition temperature when a user subsequently sits on the seat.

An electronic device having one or more components that generate heat during operation includes a structure for temperature management and heat dissipation. The structure for temperature management and heat dissipation comprises a heat transfer substrate having a surface that is in thermal communication with the ambient environment and a temperature management material in physical contact with at least a portion of the one or more components of the electronic device and at least a portion of the heat transfer substrate. The temperature management material comprises a polymeric phase change material having a latent heat of at least 5 Joules per gram and a transition temperature between 0° C. and 100° C., and a thermal conductive filler.

Aqueous dispersions are disclosed, having a minimum film formation temperature no greater than about 50° C., that include a multi-stage emulsion polymer made by a process that includes a first polymerization stage, in which a first monomer mixture having a calculated glass transition temperature of at least about 50° C. is polymerized via free radical emulsion polymerization to obtain a first-stage emulsion polymer, and a second polymerization stage, in which a second monomer mixture, having a calculated glass transition temperature from about −30° C. to about 10° C., is polymerized via free radical emulsion polymerization, in the presence of the first-stage emulsion polymer. The dispersions are useful in a variety of coating compositions that exhibit improved block resistance.

A medical device includes an inflatable balloon defining an interior surface and an exterior surface, and a coating including a therapeutic agent disposed on the exterior surface of the inflatable balloon. The coating has a release transition temperature within a range from about 25° C. to about 50° C. When the temperature of the coating is below the release transition temperature, the coating retains at least a portion of the therapeutic agent on the exterior of the inflatable balloon. When the temperature of the coating is above the release transition temperature, the coating releases at least a portion of the therapeutic agent from the exterior of the inflatable balloon.

A graftless prosthetic stent for treatment of vascular lesions such as aneurysms and arterio-venous fistulas, especially in neurovascular vessels, comprises a continuous helical ribbon formed of a shape-retaining metal having a transition temperature at which the stent expands from its contracted condition to a radially expanded condition, the stent remaining substantially cylindrical in its contracted and expanded conditions. The helical windings have variable width, thickness, number or size of openings, or combinations of these features, which affect the stiffness, rate of expansion at the transition temperature, and the area of vessel wall covered by the stent. A catheter device which includes the stent, and a method of treatment using the stent are also provided.

The gel preparation has the merits of both solution and gel. By means of the combination of different type poloxamers, ocular in-situ gel preparation containing medicine and water soluble polymer supplementary material is prepared. The preparation contains poloxamer 407 and poloxament 188 as well as water soluble polymer supplementary material less than 3%. The preparation has proper phase conversion temperatur and may form gel on the surface of cornea of living body after being applied in liquid state at room temperature. The present invention can delay the disappearance of medicine and raise the biological utilization in some local area and is suitable for various ocular medicines.

Shape memory polymers prepared by copolymerizing two monomers, which each separately produce polymers characterized by different glass transition temperatures in the presence of a difunctional monomer whereby the copolymer formed is cross-linked during the polymerization to form a theremoset network. The transition temperature of the final polymers is adjusted by the ratio of the monomers selected, to from about 20 to about 110° C., while the degree of cross-linking controls the rubbery modulus plateau. The shape memory polymers can be processed as castable formulations in the form of coatings and films. The copolymers are optically transparent and are useful as medical plastics. The invention also relates to the articles of manufacture thereof and methods of the preparation and use thereof.

A stent formed of polymeric material, useful for the expansion of a lumen and the delivery of one or more therapeutic agents in situ is disclosed. The stent may be multi-layered, and may change shape at a state transition temperature governed by the materials forming the layers. Methods of use and manufacture are also disclosed.

A system and method for performing spinal fusion using vertebral connecting rods constructed of a shape memory material, such as shape memory alloy. The connecting rod is cooled below its phase transition temperature, which is chosen to be just below body temperature, and is inserted through a curved guide tube previously inserted into the back of the patient. The guide tube is located so as to deliver the connecting rod at its desired location between the preinserted pedicle screw heads. The rod, being in its flexible state below the transition temperature, negotiates the curve and exits the guide tube in a straight form and parallel to the patient's spine. As it heats up to body temperature, it regains its original straight shape and its original rigidity, and is ready for connecting its associated vertebrae to each other.

The invention discloses a high-activity catalyst which catalyzing and activating carbon dioxide to perform the copolymerization reaction with alkylene oxide to synthesize polycarbonate. The catalyst is characterized in that the catalyst is a tetradentate schiff base complex contains one or two organic base groups and has single active site initiation and controllable polymerization. The catalyst has the advantages that under milder conditions and at lower concentration of the catalyst, the catalyst can highly and efficiently catalyze the carbon dioxide to make the copolymerization reaction with the alkylene oxide to prepare the polycarbonate, the catalytic efficiency is 10<6>g polymer/mol catalyst, the polymer molecular weight is adjusted in the range of between 5,000 and 500,000, the molecular weight distribution is less than 2, the alternating structure is over 97 percent, and the catalyst can be degraded into small molecule compounds under certain condition. By utilizing the catalyst, the telomerization reaction between the carbon dioxide and two or more than two types of alkylene oxide can be catalyzed to synthesize a polycarbonate telomer with adjusting glass transition temperature.

An electrically operated scented wax holder that forms a receptacle for receiving unmelted blocks of wax which are heated to the melting point and thereafter maintained at a safe temperature by a temperature-regulated electrical heating element. The wax receptacle is removable mounted on a base section that houses a positive temperature coefficient (PTC) thermistor which has a transition temperature substantially higher than the melting point of the wax to insure that the wax is rapidly melted, but substantially below the temperature that would constitute a danger to a human who might touch the exterior surface of the warmer, or constitute a fire hazard. The heating element is preferably placed in thermal contact with a contact pad having high thermal conductivity that is in turn placed closely adjacent to the wax receptacle, thereby efficiently transferring heat from the electrically operated temperature regulated heating element to the wax in the receptacle. A switch is positioned to de-energize the heating element whenever the wax receptacle is removed from the base section, and a visible pilot light is illuminated whenever the heating element is energized.

Phospholipid based powders for drug delivery applications are disclosed. The powders comprise a polyvalent cation in an amount effective to increase the gel-to-liquid crystal transition temperature of the particle compared to particles without the polyvalent cation. The powders are hollow and porous and are preferably administered via inhalation.

Cellulosic fibers having enhanced reversible thermal properties and applications of such cellulosic fibers are described. In one embodiment, a cellulosic fiber includes a fiber body including a cellulosic material and a set of microcapsules dispersed in the cellulosic material. The set of microcapsules contain a phase change material having a latent heat of at least 40 J/g and a transition temperature in the range of 0° C. to 100° C., and the phase change material provides thermal regulation based on at least one of absorption and release of the latent heat at the transition temperature. The cellulosic fiber can be formed via a solution spinning process, and can be used in various products where thermal regulating properties are desired.

An optical fiber is disclosed in which the core region of the optical fiber is doped with Cl and F in order to reduce the viscosity mismatch between the core region and the adjacent cladding region. In one embodiment of the invention, the optical fiber is a single-mode step index optical fiber having a core region doped with Cl and F in an amount effective to produce a difference in temperature between the glass transition temperature of the core region and the glass transition temperature of the adjacent cladding region of less than about 200° C.