Tetralogy of Fallot and absent pulmonary valve syndrome.

Absent pulmonary valve syndrome is a relatively rare condition, representing a subset of about 3% of cases of tetralogy of Fallot in both autopsy and clinical reviews (1). The syndrome is characterized by a ringlike and usually stenotic malformation rather than by the absence of the pulmonary valve, with failure of development of the valve cusps. Another important feature of absent pulmonary valve syndrome is the marked aneurysmal dilatation of the proximal pulmonary arteries, which causes extrinsic compression of the tracheobronchial tree, leading to respiratory symptoms of variable severity (2).

Aortic arch reconstruction in neonates using an autologous pericardial patch.

This video tutorial illustrates the surgical correction of aortic coarctation associated with severe hypoplastic aortic arch and a large subaortic ventricular septal defect using a fresh autologous pericardial patch for arch reconstruction under hypothermic cardiopulmonary bypass and selective cerebral perfusion.

The 4P: Preventing Preneoplasia through Patients Partnership.

The early diagnosis and management of oral potentially malignant disorders (OPMD) represent a unique opportunity to develop strategies that will prevent malignant transformation. Despite a high prevalence, awareness remains low, patient outcomes poor, and quality of life highly affected. How can patient advocacy groups (PAGs) bring more awareness to preneoplasia preceding oral cancers and help patients after the identification of a suspicious oral leukoplakia presented as white patches in the mouth? PAGs are today involved with awareness campaigns, lobbying, and education of both health care systems as well as the survivor and the newly diagnosed.

Thermodynamic evidence of giant salt deposit formation by serpentinization: an alternative mechanism to solar evaporation.

The evaporation of seawater in arid climates is currently the main accepted driving mechanism for the formation of ancient and recent salt deposits in shallow basins. However, the deposition of huge amounts of marine salts, including the formation of tens of metres of highly soluble types (tachyhydrite and bischofite) during the Aptian in the South Atlantic and during the Messinian Salinity Crisis, are inconsistent with the wet and warm palaeoclimate conditions reconstructed for these periods. Recently, a debate has been developed that opposes the classic model of evaporite deposition and argues for the generation of salt by serpentinization.

Formation of stromatolite lamina at the interface of oxygenic-anoxygenic photosynthesis.

In modern stromatolites, mineralization results from a complex interplay between microbial metabolisms, the organic matrix, and environmental parameters. Here, we combined biogeochemical, mineralogical, and microscopic analyses with measurements of metabolic activity to characterize the mineralization processes and products in an emergent (<18 months) hypersaline microbial mat. While the nucleation of Mg silicates is ubiquitous in the mat, the initial formation of a Ca-Mg carbonate lamina depends on (i) the creation of a high-pH interface combined with a major change in properties of the exopolymeric substances at the interface of the oxygenic and anoxygenic photoautotrophic layers and (ii) the synergy between two major players of sulfur cycle, purple sulfur bacteria, and sulfate-reducing bacteria.