Covered Versus Uncovered Metal Stents for the Drainage of the Malignant Distal Biliary Obstruction With ERCP: A Systematic Review and Meta-Analysis.

Introduction And Aim: Unresectable malignant distal biliary obstruction is a condition that should be treated with drainage and clearance of the biliary duct. self-expanded metal stents (SEMS) are known to be better and more effective than plastic stents because the patency is longer. The actual evidence is insufficient to recommend if it is better the use of SEMSu over SEMSc or vice versa for the drainage of the malignant distal biliary obstruction during ERCP.

Solubility and Thermodynamic Parameters of HS/CH in Ionic Liquids Determined by H NMR.

Natural gas remains an important global source of energy. Usually, sour gas from the well or refinery stream contains HS among other contaminants that should be removed to fulfill permissible standards of use. Despite the use of different gas-liquid sour gas upgrading technologies, ionic liquids (ILs) have been recognized as promising materials to remove HS from sour gas.

Bioequivalence and Tolerability of Ambrisentan: A Pharmacokinetic Study in Mexican Healthy Male Subjects.

Background: Pulmonary arterial hypertension (PAH) is a disease characterized by a progressive rise in pulmonary vascular resistance. Ambrisentan is an oral, propanoic acid based-endothelin receptor antagonist (ERA), selective for the endothelin type-A receptor, which is approved for the treatment of PAH. The Colombia National Food and Drug Surveillance Institute regulatory criteria require demonstrating that the proposed generic product is bioequivalent to its reference-listed drug to obtain marketing approval.

[Safety of gastroenterologist-directed propofol administration for endoscopic procedures: 10-year experience in a private clinic in Lima, Peru].

Objective: To evaluate safety of propofol combined with Meperidine and Midazolam in colonoscopies, upper endoscopies (EGD) and Endoscopic Ultrasound (EUS) administered by a nurse supervised by a trained gastroenterologist. To compare the required doses of propofol among older and younger than 75 years old.

Materials And Methods: Retrospective descriptive study including patients 18 years of age and older who received propofol for EGD, colonoscopy (or EGD + colonoscopy) and EUS.

The effect of the central donor in bis(benzimidazole)-based cobalt catalysts for the selective cis-1,4-polymerisation of butadiene.

A series of bis(benzimidazole)-based cobalt(II) dichloride complexes containing a range of different central donors has been synthesized and characterized. The nature of the central donor affects the binding of the ligand to the cobalt centre and determines the coordination geometry of the metal complexes. All complexes have been shown to catalyse the polymerization of butadiene, in combination with MAO as the co-catalyst, to give cis-1,4-polybutadiene with high selectivity.

An unprecedented alpha-olefin distribution arising from a homogeneous ethylene oligomerization catalyst.

Treatment of the bis(benzimidazolyl)amine chromium complex 2 with ethylene in the presence of MAO affords an exceptionally active oligomerization catalyst and an unprecedented distribution of 1-olefin products in which the C4n series is much more abundant than the C4n+2 series. Deuterium labeling studies are consistent with a metallacyclic chain growth mechanism in which the unusual product distribution arises from the interplay of two sites.

Experimental evidence for large ring metallacycle intermediates in polyethylene chain growth using homogeneous chromium catalysts.

Deuterio-ethylene labeling studies on two homogeneous chromium ethylene oligomerization catalysts show that chain propagation proceeds via metallacyclic intermediates; reactions performed in the presence of 1-nonene show no incorporation of the higher olefin, strongly implicating the involvement of large ring metallacycles.