摘要:
A method and apparatus for mitigating dynamic overvoltage (DOV) in an AC network. A distribution and power transformer has its primary connected to the high voltage bus of the network and its secondary connected to a switching device. Upon the occurrence of a condition known to cause a DOV and the DOV a control system cause the switching device to change from a nonconductive mode to a conductive mode in less than the time for one cycle of the operating frequency of the AC network. This change in switching device conduction places a short circuit across the transformer secondary.
摘要:
A distribution and power transformer has its primary connected to the high voltage bus of the network and its secondary connected to a switching device. Upon the occurrence of a condition known to cause a dynamic overvoltage (DOV) and the occurrence of the DOV, a control system causes the switching device to change from a nonconductive mode to a conductive mode in less than the time for one cycle of the operating frequency of the AC network. This change in switching device conduction places a short circuit across the transformer secondary and thus mitigates the DOV.
摘要:
Described herein are tissue grafts derived from the placenta that possess good adhesion to biological tissues and are useful in would healing applications. In one aspect, the tissue graft includes (1) two or more layers of amnion, wherein at least one layer of amnion is cross-linked, (2) two or more layers of chorion, wherein at least one layer of amnion is cross-linked, or (3) one or more layers of amnion and chorion, wherein at least one layer of amnion and/or chorion is cross-linked. In another aspect, the grafts are composed of amnion and chorion cross-linked with one another. In a further aspect, the grafts have one or more layers sandwiched between the amnion and chorion membranes. The amnion and/or the chorion are treated with a cross-linking agent prior to the formation of the graft. Also described herein are methods for making and using the tissue grafts.
摘要:
A method for preparing placenta membrane tissue grafts for medical use, includes obtaining a placenta from a subject, cleaning the placenta, separating the chorion tissue from the amniotic membrane, mounting a selected layer of either the chorion tissue or the amniotic membrane onto a drying fixture, dehydrating the selected layer on the drying fixture, and cutting the selected layer into a plurality of tissue grafts. Preferably, the drying fixture includes grooves or raised edges that define the outer contours of each desired tissue graft, after they are cut, and further includes raised or indented logos that emboss the middle area of the tissue grafts during dehydration and that enables an end user to distinguish the top from the bottom side of the graft. The grafts are comprised of single layers of amnion or chorion, multiple layers of amnion or chorion, or multiple layers of a combination of amnion and chorion.
摘要:
Described herein are tissue grafts derived from the placenta. The grafts are composed of at least one layer of amnion tissue where the epithelium layer has been substantially removed in order to expose the basement layer to host cells. By removing the epithelium layer, cells from the host can more readily interact with the cell-adhesion bio-active factors located onto top and within of the basement membrane. Also described herein are methods for making and using the tissue grafts. The laminin structure of amnion tissue is nearly identical to that of native human tissue such as, for example, oral mucosa tissue. This includes high level of laminin-5, a cell adhesion bio-active factor show to bind gingival epithelia-cells, found throughout upper portions of the basement membrane.
摘要:
A method for preparing placenta membrane tissue grafts for medical use, includes obtaining a placenta from a subject, cleaning the placenta, separating the chorion tissue from the amniotic membrane, mounting a selected layer of either the chorion tissue or the amniotic membrane onto a drying fixture, dehydrating the selected layer on the drying fixture, and cutting the selected layer into a plurality of tissue grafts. Preferably, the drying fixture includes grooves or raised edges that define the outer contours of each desired tissue graft, after they are cut, and further includes raised or indented logos that emboss the middle area of the tissue grafts during dehydration and that enables an end user to distinguish the top from the bottom side of the graft. The grafts are comprised of single layers of amnion or chorion, multiple layers of amnion or chorion, or multiple layers of a combination of amnion and chorion.
摘要:
Described herein are tissue grafts derived from the placenta. The grafts are composed of at least one layer of amnion tissue where the epithelium layer has been substantially removed in order to expose the basement layer to host cells. By removing the epithelium layer, cells from the host can more readily interact with the cell-adhesion bio-active factors located onto top and within of the basement membrane. Also described herein are methods for making and using the tissue grafts. The laminin structure of amnion tissue is nearly identical to that of native human tissue such as, for example, oral mucosa tissue. This includes high level of laminin-5, a cell adhesion bio-active factor show to bind gingival epithelia-cells, found throughout upper portions of the basement membrane.
摘要:
A method for preparing placenta membrane tissue grafts for medical use, includes obtaining a placenta from a subject, cleaning the placenta, separating the chorion tissue from the amniotic membrane, mounting a selected layer of either the chorion tissue or the amniotic membrane onto a drying fixture, dehydrating the selected layer on the drying fixture, and cutting the selected layer into a plurality of tissue grafts. Preferably, the drying fixture includes grooves or raised edges that define the outer contours of each desired tissue graft, after they are cut, and further includes raised or indented logos that emboss the middle area of the tissue grafts during dehydration and that enables an end user to distinguish the top from the bottom side of the graft. The grafts are comprised of single layers of amnion or chorion, multiple layers of amnion or chorion, or multiple layers of a combination of amnion and chorion.
摘要:
An antimicrobial additive composition is provided which economically and efficiently imparts antimicrobial characteristics to acrylic polymers, and particularly thermoformable acrylic sheets made from such polymers. The antimicrobial composition contains 2,4,4′-trichloro-2′-hydroxydiphenyl ether, also known as triclosan, and orthophenyl phenol also known as OPP.
摘要:
A method is specified for operating a charger (1) for a voltage-maintaining device (2), in which a rectifier (5), connected to phase inputs (PA, PB; PC) via a transformer (3) with an electric AC voltage supply system (4), of the charger (1) is driven by means of a drive signal (S) formed from reference charging voltages (ULA, ref; ULB, ref; ULC, ref). Furthermore, a charging voltage (ULA; ULB; ULC) for the corresponding phase (A; B; C) is generated at each phase input (PA; PB; PC) a substantially constant DC voltage (UDC) being generated-on the DC voltage side of the rectifier (5). Each charging voltage (ULA; ULB; ULC) is generated in such a way that in the corresponding phase (A; B; C) a charging current (ILA; ILB; ILC) is injected in a fashion substantially proportional to a phase system voltage (UNA; UNB; UNC) of the corresponding phase (A; B; C) of the electric AC voltage supply system (3). An apparatus for carrying out the method is also disclosed.