Experimental study of a positive surge. Part 1: Basic flow patterns and wave attenuation

A positive surge results from a sudden change in flow that increases the depth. It is the unsteady flow analogy of the stationary hydraulic jump and a geophysical application is the tidal bore. Positive surges are commonly studied using the method of characteristics and the Saint-Venant equations. The paper presents the results from new experimental investigations conducted in a large rectangular channel. Detailed unsteady velocity measurements were performed with a high temporal resolution using acoustic Doppler velocimetry and non-intrusive free-surface measurement devices. Several experiments were conducted with the same initial discharge (Q=0.060 m³/s) and 6 different gate openings after closure resulting in both non-breaking undular and breaking bores. The analysis of undular surges revealed wave amplitude attenuation with increasing distance of surge propagation were in agreement with Ippen and Kulin theory. Also, undular wave period and wave length data were relatively close to the values predicted by the wave dispersion theory for gravity waves in intermediate water depths

Phase II drugs that are currently in development for the treatment of cachexia

Cachexia is a syndrome presenting with progressive unintentional weight loss and wasting and weakness of skeletal muscle. Cachexia is prevalent in cancer and in chronic diseases including chronic obstructive pulmonary disease (COPD). Areas covered: The authors searched trial registers for current Phase II clinical trials on cachexia. Twelve studies were found with 11 compounds, including the anti-inflammatory drugs thalidomide, OHR/AVR118, celecoxib, VT-122, omega-3 supplements, and anabolic agents such as ghrelin analogues, MT-102, BYM338 and ruxolotinib. The authors note that one of the studies related to COPD while the others were related to different cancers. Herein, the authors describe the mechanisms of action and their Phase II study design. Expert opinion: The compounds under study affect several pathways involved in cachexia by modulating inflammatory activity, anabolic potential, digestion and direct interaction with the muscle. Due to the multifactorial aspects of cachexia syndrome, combinations of these new drugs with nutritional intervention is probably the most promising approach. Furthermore, future studies should include interventions in pre-cachetic patients, as this stage might be more responsive to treatment. Future studies will benefit from well-defined end points and improved measures of cachexia, providing new insight into the disease. This insight, in combination with the elucidation of cachexia's underlying mechanism, will yield new treatment strategies in the near future