BACKGROUND AND OBJECTIVE Because the effectiveness of diphtheria-tetanus-acellular pertussis (DTaP) vaccine wanes substantially after the fifth dose at ages 4 to 6 years, there is a growing cohort of adolescents who rely on tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) for protection against pertussis. Yet despite high Tdap vaccine coverage among adolescents, Califor...

Picture 1. A, Barium enema showed dislocation of the descending colon (arrows). B, Ultrasonography depicted a high-echogenic mass with low-echoic crescent. C, Computed tomography with contrast enhancement represented a slightly enhanced mass with low-density crescent (arrow). D, T1-weighted magnetic resonance image (MRI) demonstrated low-intensity mass with high-intensity crescent (arrow). E, B...

Posterior iliac crescent fracture-dislocation is generally considered rotationally unstable and vertically stable. The current study (1) investigated whether vertical instability may occur in posterior iliac crescent fracture-dislocation and (2) analyzed the clinical features of vertically unstable iliac crescent fracture-dislocation as well as treatment strategies. Patients with pelvic fractur...

We predict a family of 2D carbon (C) allotropes, square graphynes (S-graphynes) that exhibit highly anisotropic Dirac fermions, using first-principle calculations within density functional theory. They have a square unit-cell containing two sizes of square C rings. The equal-energy contour of their 3D band structure shows a crescent shape, and the Dirac crescent has varying Fermi velocities fro...

We read with great interest the well-written article by Tseng and Chen, 1 who described the case of a 65-year-old woman who presented with hemoptysis and a cavitary lesion in the right lung with an air crescent sign and an intracavitary fungus ball-like mass. The final diagnosis was lung carcinoma. The authors highlighted the importance of cavity wall thickness for the differential diagnosis, r...