Distal duodenal web with malrotation: An unusual finding.

The most common site of the congenital duodenal web is the second part. Web distal to the second part of the duodenum is rare. It mimics the windsock deformity. Diagnosis may be missed if accompanying malrotation is present. We hereby report two cases of distal duodenal webs associated with malrotation and challenges in their diagnosis and management.

Control over product formation and thermodynamic stability of thiolate-protected gold nanoclusters through tuning of surface protecting ligands.

Surface-protecting ligands can regulate the structure of a cluster's core either through electronic or steric effects. However, the influence of the steric effect along with the electronic effect over controlling the structure during ligand exchange reactions remains elusive. To understand this, we have carried out ligand exchange on [Au23(CHT)16]- (CHT: cyclohexane thiol) using aromatic thiolates where we have tuned the bulkiness at the para position of the thiolate group on the incoming ligands. The outcome of the experiments reveals that each of the ligands in the chosen series is precisely selective towards the parent cluster transformation through specific intermediates. The ligand with more steric crowding directed the reaction pathway to have Au28 nanocluster as the major product while Au36 was the final product obtained with the gradual decrease of bulkiness over the ligand. The combined experimental and theoretical results elucidated the mechanism of the reaction pathways, product formation, and their stability. Indeed, this study with the series of ligands will add up to the ligand library, where we can decide on the ligand to obtain our desired cluster for specific applications through the ligand exchange reaction.

Congenital Segmental Dilatation of Ascending Colon with Distal Microcolon: A Diagnostic Dilemma.

A 5-day-old male presented with bilious vomiting, a grossly distended abdomen, and passage of a small amount of stool. The anal opening was at a normal position. X-ray abdomen showed a large bowel loop with a single air-fluid level occupying more than half of the abdominal width. On laparotomy, the ascending colon was dilated to form a pouch-like structure, and the ileum and appendix were opening into it. Colon distal to pouch was present as microcolon. Histopathology of the dilated segment was suggestive of congenital segmental dilatation (CSD). In CSD, the distal bowel is of normal caliber. This is a rare case of CSD of ascending colon with distal microcolon.