Interaction of human immunodeficiency virus (HIV) glycans with lectins of the human immune system

Approximately half of the molecular mass of gp120, the receptor-binding envelope protein of human immunodeficiency virus (HIV), consists of N-linked glycans. Nearly half of these glycans are of the high mannose type. These high mannose glycans furnish a rich forest of mannose residues on the virus surface making HIV a prime target for interaction with mannose-specific lectins of the immune system. This review focuses on the known interactions between gp120 and immune system lectins some of which HIV appears to exploit. The effect of variation in glycosylation of gp120, especially with respect to clades of HIV, on binding of immune system lectins is highlighted.     

An investigation of motion correction algorithms for pediatric spinal cord DTI in healthy subjects and patients with spinal cord injury

Patient and physiological motion can cause artifacts in DTI of the spinal cord which can impact image quality and diffusion indices. The purpose of this investigation was to determine a reliable motion correction method for pediatric spinal cord DTI and show effects of motion correction on DTI parameters in healthy subjects and patients with spinal cord injury. Ten healthy subjects and ten subjects with spinal cord injury were scanned using a 3 T scanner. Images were acquired with an inner field-of-view DTI sequence covering cervical spine levels C1 to C7. Images were corrected for motion using two types of transformation (rigid and affine) and three cost functions. Corrected images and transformations were examined qualitatively and quantitatively using in-house developed code. Fractional anisotropy (FA) and mean diffusivity (MD) indices were calculated and tested for statistical significance pre- and post- motion correction. Images corrected using rigid methods showed improvements in image quality, while affine methods frequently showed residual distortions in corrected images. Blinded evaluation of pre and post correction images showed significant improvement in cord homogeneity and edge conspicuity in corrected images (p < 0.0001). The average FA changes were statistically significant (p < 0.0001) in the spinal cord injury group, while healthy subjects showed less FA change and were not significant. In both healthy subjects and subjects with spinal cord injury, quantitative and qualitative analysis showed the rigid scaled-least-squares registration technique to be the most reliable and effective in improving image quality.     

The Doyen-Wilson theorem for kite systems

Necessary and sufficient conditions are given to embed a kite system of order n into a kite system of order m.     

Configurations in bowtie systems

There are ten configurations of two bowties that can arise in a bowtie system. We determine a basis for configurations of two bowties in both balanced and general bowtie systems. We also determine the avoidance spectrum for the three most compact configurations of two bowties.