Impact Toughness Modification of NIST Low-Energy Charpy Verification Specimens for Testing at Room Temperature.

The possibility for the National Institute for Standards and Technology (NIST) to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of -40 °C was investigated in a previous study, in which a slightly increased likelihood of specimen jamming was observed at the low-energy level (13 J to 20 J). Moreover, there is a concern that the higher impact toughness of low-energy verification specimens at room temperature would not allow the same Charpy machine features to be verified as in the case of low-temperature (-40 °C) tests, namely, the linear elastic behavior of the sample and the very high maximum forces (typically larger than 33 kN). In this paper, we report on the change in the mechanical properties (hardness and absorbed energy) of the American Iron and Steel Institute (AISI) 4340 steel low-energy specimens that ensues from the modification of the temperature of the final tempering heat treatment.

Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens.

The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of -40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e.

[Effectiveness and safety of lansoprazole in the treatment of peptic ulcer].

Background: Lansoprazole, a new proton pump inhibitor, is now available in Mexico. It has been tested elsewhere with excellent results.

Aim: To study its safety and efficacy in Mexican patients.

[Sodium benzoate in portal-systemic-encephalopathy-induced blood ammonia normalization and clinical improvement. Interim report of a double-blind multicenter trial].

To investigate the therapeutic efficacy of sodium benzoate (SB) in a cirrotic population with chronic portal systemic encepalopathy (PSE), we performed a double blind, randomised, multicentric, clinical trial, comparing SB versus a standard therapy of lactitol (LA). To perform the study blind, syrups containing the two drugs were prepared. To date 27 patients have been studied.

[A 10-year prolective study on cancer of the digestive system].

Objective: A ten year prolective and multicentre study of cancer of the Digestive Tract aims to evaluate the variations on frequency and to identify risk factors.

Methods: Ten hospitals are participating five in Mexico City and five in other states. Data were obtained through the hospitals files and specially designed questionnaires, the latter mainly diet and habits oriented.

[Prophylactic effect of Misoprostol on gastric lesions induced by aspirin (ASA) in healthy subjects].

Aspirin (ASA) and other nonsteroidal anti-inflammatory drugs (NSAIDs), are extensively used for treating rheumatic diseases, inflammatory problems, and pain of different etiologies. However, their use is limited by the damage they may produce to the gastroduodenal mucosa. The purpose of this double-blind, multicenter, randomized, placebo-controlled study was to assess and corroborate the protective effect of misoprostol on the gastric mucosa against ASA injury.