Hilar Tumours

Tumours that involve the confluence of the bile ducts in the liver hilum provide a major therapeutic challenge. Adequate palliation requires relief of jaundice. Even though jaundice can be relieved if only 30% of the liver is drained, the presence of undrained bile ducts may result in pruritus and a continued risk of cholangitis and hepatic abscess. The biliary anatomy is defined by cholangiography, which today can be performed by magnetic resonance; the stricture is dilated, and plastic or metallic stents are endoscopically inserted over a guidewire. Patients with complex hilar strictures may benefit from the insertion of one or more stents, although there is debate about how many are necessary. The present article provides specific technical details, describes comparative trials of unilateral versus bilateral biliary drainage and explores new techniques that warrant further investigation

A Rational Approach Towards a New Ferrocenyl Pyrrolidine for Stereoselective Enamine Catalysis

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Hilar Tumours

Tumours that involve the confluence of the bile ducts in the liver hilum provide a major therapeutic challenge. Adequate palliation requires relief of jaundice. Even though jaundice can be relieved if only 30% of the liver is drained, the presence of undrained bile ducts may result in pruritus and a continued risk of cholangitis and hepatic abscess. The biliary anatomy is defined by cholangiography, which today can be performed by magnetic resonance; the stricture is dilated, and plastic or metallic stents are endoscopically inserted over a guidewire. Patients with complex hilar strictures may benefit from the insertion of one or more stents, although there is debate about how many are necessary. The present article provides specific technical details, describes comparative trials of unilateral versus bilateral biliary drainage and explores new techniques that warrant further investigation

Chapter 26: Alpha-Alkylation by SN1-Type Reactions

Non Previsto Summary SN1-Type Nucleophilic Reaction by Generation of Carbocations Organocatalytic Stereoselective SN1-Type Reactions with Enamine Catalysis Asymmetric SN1-Type \u3b1-Alkylation of Ketones Combination of Enamine Catalysis and Lewis Acids in SN1-Type Reactions Organocatalytic SN1-Type Reactions with Br\uf8nsted Acids SN1-Type Reaction Promoted by Chiral Thioureas SN1-Type Organocatalytic Reaction of Iminium, Oxonium, and Aziridinium Intermediate

The Facile and Direct Formylation of Organoboron Aromatic Compounds with Benzodithiolylium Tetrafluoroborate

Organoboron compounds can be used to effect a direct formylation in the absence of transition metals. We report that the direct reaction between boronic derivatives and benzodithiolylium tetrafluoroborate, a commercially available carbenium ionic compound, is possible and provides access to many interesting compounds without the use of transition metals. The direct reaction of the carbenium ion with boronic derivatives results in the formation of substituted arylcarbenium ions, a number of which can be further utilized in materials chemistry or for the direct transformation into other compounds. In addition to the rich chameleonic chemical nature of the benzodithiol intermediate, such species can also undergo a metallation reaction and subsequent treatment with a wide range of electrophiles to access a variety of functional groups (aldehyde, ketone, acid, and alkyl groups)

On the Use of Ultrasonic Flowmeters for Cooling Energy Metering and Sub-Metering in Direct Expansion Systems

The Energy Efficiency Directive (EED, Directive 2012/27/EU) has made mandatory the installation of individual metering systems in the case of buildings with centralized heating/cooling and hot water sources (multi-apartment and multi-purpose buildings), provided it is economically and technically feasible. Individual metering of heating/cooling systems is mainly based on thermal energy meters (TEM), which are widely used for direct metering in heating applications. On the other hand, direct metering of energy consumption in cooling systems still represents a challenge, given the different types of cooling units and the lack of regulations from the technical and legal points of view. In this context, this paper briefly overviews the available centralized cooling systems and the possible solutions for metering and sub-metering, which depend on the specific application. Vapour Compression Refrigeration (VCR) systems are spreading worldwide for air conditioning applications. Particular attention has been paid to the direct metering of cooling energy and specifically to refrigerant flow rate measurement, which represents a critical issue because of the small-diameter pipes and the different thermodynamic properties of the fluid used. Thus, an experimental campaign has been developed and carried out in order to compare a clamp-on ultrasonic flowmeter with a more accurate Coriolis one in a direct expansion (DE) system. The experimental tests have been performed at two different temperature conditions, showing a relative error in the mass flow rate measurements within ±10%