摘要:
A new mold solves problems that arise from differential changes in geometry inherent to casting metal in a ceramic mold, by control of the internal morphology between the surfaces of the mold that face the casting, and that face the external environment. Layered fabrication techniques are used to create a ceramic mold. For example, an internal geometry composed of a cellular arrangement of voids may be created within the mold wall. Structures may be designed and fabricated so that the ceramic mold fails at an appropriate time during the solidification and/or cooling of the casting. Thus, the casting itself is not damaged. The mold fails to avoid rupture, or even distortion, of the casting. A thin shell of ceramic defines the casting cavity. This shell must be thin enough to fail due to the stresses induced (primarily compressive) by the metal next to it and partly adherent to it. A support structure is provided with a morphology that supports the thin shell that defines the casting geometry, yet that also fails as the casting solidifies and/or cools. Typically, the support structure is a skeletal network with voids therebetween. The skeletal elements may be struts, or sheets or both. At least the following two failure mechanisms may be exploited in the design of the support structure: bending in the structure; and under compressive loads, either by buckling of a support member or, breakage under compressive loading. The failure of the support structure may also be due to a combination of bending and compression.
摘要:
Solid free-form (SSF) techniques for making medical devices for implantation and growth of cells from polymers or polymer/inorganic composites using computer aided design are described. Examples of SFF methods include stereo-lithography (SLA), selective laser sintering (SLS), ballistic particle manufacturing (BPM), fusion deposition modeling (FDM), and three dimensional printing (3DP). The devices can incorporate inorganic particles to improve the strength of the walls forming the pores within the matrix and to provide a source of mineral for the regenerating tissue. The devices can contain tissue adhesion peptides, or can be coated with materials which reduce tissue adhesion. The macrostructure and porosity of the device can be manipulated by controlling printing parameters. Most importantly, these features can be designed and tailored using computer assisted design (CAD) for individual patients to optimize therapy.
摘要:
Microchip delivery devices are provided that control both the rate and time of release of molecules, wherein the device includes a substrate, at least one reservoir in the substrate containing the molecules, and a reservoir cap positioned on the reservoir over the molecules, wherein the molecules are released from the reservoir upon heating or cooling the device or a portion thereof sufficient to rupture the reservoir cap. In a preferred embodiment, the device includes a resistor integrated into the reservoir or mounted near the reservoir, which upon application of an electric current through the resistor, causes at least one of the contents of the reservoir to thermally expand, vaporize, phase change, or undergo a thermally driven reaction, such that the reservoir cap ruptures due to mechanical stress. In another preferred embodiment, application of an electric current to a resistor located on or near the reservoir cap causes the cap to expand, contract, or undergo a phase change that results in the rupture of the reservoir cap. The reservoirs can contain multiple drugs or other molecules in variable dosages. Each of the reservoirs of a single microchip can contain different molecules and/or different amounts and concentrations, which can be released independently.
摘要:
Apparati and methods are provided for the delivery of molecules to a site via a carrier fluid. The apparati include microchip devices which have reservoirs containing the molecules for release. The apparati and methods provide for active or passive controlled release of the molecules. Preferred embodiments include systems for intravenous administration of drugs, wherein drug molecules are released from the microchip devices into a carrier fluid ex vivo, such as a saline solution, forming a drug/saline solution mixture which is then delivered to a patient intravenously.
摘要:
A process for making a component by depositing a first layer of a powder material in a confined region and then depositing a binder material to selected regions of the layer of powder material to produce a layer of bonded powder material at the selected regions. Such steps are repeated a selected number of times to produce successive layers of selected regions of bonded powder material so as to form the desired component. The unbonded powder material is then removed. In some cases the component may be further processed as, for example, by heating it to further strengthen the bonding thereof.
摘要:
Highly-textured superconductor oxide thin films are prepared on substrates, including lattice matched, non-lattice matThe Government has rights in this invention pursuant to contract Number MDA972-88-K0006 awarded by the U.S. Defense Advance Research Project Agency.
摘要翻译:通过金属有机沉积(MOD)在衬底上制备高纹理超导体氧化物薄膜,包括晶格匹配的,非晶格匹配的惰性和非惰性材料。 选择前体溶液组成以及加工温度和气氛以控制瞬态液相的存在。 以高度纹理化的形态和完全致密均匀的微观结构为特征的超导体氧化物膜在77°K时能够保持超过104A / cm 2的临界电流密度,当在非晶格匹配衬底上制备时,其临界电流密度超过106A / cm2,当在晶格匹配的基底上制备时。
摘要:
A method delivers an implantable device through the urethra and into the bladder. A deployment instrument is inserted into the urethra, the implantable device is inserted into the deployment instrument, and a stream of fluid is injected into the deployment instrument. The stream of fluid drives the implantable device from the deployment instrument into the bladder. The deployment instrument is removed from the urethra, leaving the implantable device wholly implanted in the bladder.
摘要:
Trapping devices and methods are provided for capturing a medical analyte, in blood or another biological fluid. The device may include a structural substrate and a binding agent, such as an antibody, affixed to the structural substrate, wherein the binding agent is capable of binding or attaching with a medical analyte, such as a viral particle, and the device is configured for placement in a biological cavity or vessel (containing a biological fluid) in a patient. The trapping device, which may be in a twisted coil shape, is configured to trap at least some of the medical analyte, such a viral particle, present in the biological fluid. The method may include deploying a trapping device into the patient's blood vessel; after a period following the deployment, removing the trapping device from the biological cavity or blood vessel; and then analyzing the trapping device for the presence of the medical analyte.
摘要:
The present invention provides systems, devices, and related methods, involving electrochemical actuation. In some cases, application of a voltage or current to a system or device of the invention may generate a volumetric or dimensional change, which may produce mechanical work. For example, at least a portion of the system may be constructed and arranged to be displaced from a first orientation to a second orientation. Systems such as these may be useful in various applications, including pumps (e.g., infusion pumps) and drug delivery devices, for example.
摘要:
A method is provided for local controlled delivery of a drug to the seminal vesicle, the prostate, the ejaculatory duct, or the vas deferens of a patient in need of treatment. In one embodiment, the method includes implanting a resorbable drug delivery device within the seminal vesicle, the prostate, the ejaculatory duct, or the vas deferens of the patient. The drug delivery device may include an elastic device body housing at least one drug reservoir which contains at least one drug. In a preferred embodiment, the method further includes releasing the drug from the device in a controlled manner to, typically directly to, the seminal vesicle, the prostate, the ejaculatory duct, or the vas deferens.