摘要:
The present disclosure provides a method that efficiently produces (6R)-tetrahydrobiopterin of Formula I in high yield and purity. The method includes the step of hydrolyzing diacetylbiopterin to biopterin under basic conditions in a biphasic mixture comprising an organic phase and an aqueous phase. After substantially complete hydrolysis of diacetylbiopterin, the aqueous phase containing biopterin can be separated from the organic phase containing most of the organic impurities, which avoids the time-consuming step of isolating biopterin as a solid. The aqueous solution containing biopterin is stereoselectively hydrogenated to (6R)-tetrahydrobiopterin under basic conditions and high hydrogen pressure in the presence of a metal catalyst (e.g., a platinum catalyst). To improve the purification of an acid addition salt of (6R)-tetrahydrobiopterin (e.g., (6R)-tetrahydrobiopterin dihydrochloride), any residual salts (e.g., sodium salts) in the aqueous solution after the hydrogenation reaction can be removed by contacting the aqueous solution with an ion (e.g., cation) exchange resin or column. Alternatively, removal of residual salts from the aqueous solution can be omitted if an organic amine (e.g., diethylamine or triethylamine) rather than an inorganic base is used in the hydrolysis and/or hydrogenation reactions.
摘要:
An electromotive linear drive with a drive unit having a drive motor and a spindle driven by the drive unit. The drive includes a spindle nut disposed on the spindle. The spindle nut is movable longitudinally on the spindle. A lifting tube is operatively connected to the spindle nut so that the spindle nut moves together with the lifting tube. A connecting part is disposed on a free end of the lifting tube. A braking assembly is disposed in the lifting tube and is operatively connected to the spindle nut via an adjustable, frictional connection. The braking assembly is manipulable. During operation of the drive motor, the spindle nut frictionally engages the braking assembly, preventing rotation of the spindle nut. The frictional connection may be adjusted to permit the spindle nut to rotate with respect to the spindle, thereby manipulating a linear speed component of the lifting tube.
摘要:
The invention relates to a tube bundle reactor with a flat feed hood. Alternatively, the release hood may also have a flat design. The flat design reduces the heat of reaction which arises in the hood in the case of reaction types which take place not only in the tube bundle (uncatalyzed reactions and reactions with homogeneously distributed catalyst). This greatly suppresses undesired reactions which already take place in the hood owing to accumulated heat, which achieves a higher selectivity in the case of thermally sensitive reactions. In addition, the thermal distribution within the hoods can be controlled precisely.The tube bundle reactor comprises a tube bundle which has a feed end which is connected to a feed hood of the tube bundle reactor, wherein the feed hood is configured in a flat design with a cross-sectional area at the feed end and an internal volume, and the ratio of internal volume to cross-sectional area is less than 0.35 m. The invention is further implemented by means of a process for operating a tube bundle reactor, comprising: introducing a reactant mixture into a tube bundle and converting at least a proportion of the reactant mixture within the tube bundle to a product. The introducing comprises: feeding the reactant mixture into an interior of a feed hood of the tube bundle reactor and passing the reactant mixture on into a feed end of the tube bundle in the form of a fluid stream. The fluid stream has a cross-sectional area on entry into the feed end, and the interior of the feed hood through which the fluid stream flows has an internal volume; where the ratio of internal volume to cross-sectional area is less than 0.35 m.
摘要:
It is described a method for distributing radio resources between a first radio link between a primary network element being assigned to a first hierarchic level of a network and a first secondary network element being assigned to a second hierarchic level and a second radio link between the primary network element and a second secondary network element being assigned to the second hierarchic level. The method includes (a) transmitting respectively a first resource allocation parameter from the first and the second secondary network element to a decision unit, the first resource allocation parameter being indicative for a minimum performance requirement, (b) transmitting respectively a second resource allocation parameter from the first and the second secondary network element to the decision unit, the second resource allocation parameter being indicative for a performance increase for the respective radio link following an allocation of additional radio resources, and (c) distributing the radio resources between the first and the second radio link based on the first and the second resource allocation parameter.
摘要:
The invention relates to a process and a device for establishing the authenticity of the identity of a service user relative to a service provider for release of an access authorization (password) for a service using two different data input terminals, a registration server and a message converter.
摘要:
The invention regards a hearing aid comprising a receiver and a signal processing device, wherein the signal processing device is electrically coupled to a connection socket operable to detachably connect the receiver to the socket and whereby the signal processing device further comprise a detector operable to detect a characteristics of the receiver which is connected to the signal processing device through the connection socket. The present invention addresses the problem of identification of individual receiver properties as well as of identifying different types of receivers.
摘要:
The present invention relates to a process for purifying a composition (I) comprising at least one cyclic ketone having from 7 to 16 carbon atoms, which comprises thermal treatment of the composition (I) with a catalyst comprising at least one transition metal and further purification by means of a process selected from the group consisting of distillation, extraction and crystallization. Furthermore, the present invention relates to a process for preparing cyclododecanone, which comprises such a purification, and the use of at least one catalyst comprising at least one transition metal for purifying a composition (I) comprising at least one cyclic ketone having from 7 to 16 carbon atoms by thermal treatment of the composition (I) with a catalyst comprising at least one transition metal.
摘要:
The present invention relates to a pharmaceutical combination product for cancer therapy. The combination product comprises the two active ingredients glutaminase and 6-diazo-5-oxo-L-norleucine (DON). The invention further relates to the use of such a combination product for the treatment of cancers.
摘要:
A grinding device for the flats of a card comprises elastically bendable elements which enter between the clothing points, brush over the side flanks of the points and thereby grind the points. Additional grinding elements are provided in order to treat the front sides of the clothing points. The ground-off material may be removed by a suction device.
摘要:
The invention relates to a driver circuit with a circuit node (10), at least two first transistors (P1, P2), the load sections of which are switched in series and connect the circuit node (10) with a first voltage (U10), at least two second transistors (N1, N2), the load sections of which are switched in series and connect the circuit node (10) with a reference potential, and a control circuit (P3–P6, N3, D1–D4, R1, 16), which is formed in order to regulate at least a first control voltage (Up2) on at least one transistor (P2) of the at least two first transistors (P1, P2) and at least a second control voltage (UN2) on at least one transistor (N2) of the at least two second transistors (N1, N2) dependent on a voltage at the circuit node (10).