This paper is concerned with feature screening and variable selection for varying coefficient models with ultrahigh dimensional covariates. We propose a new feature screening procedure for these models based on conditional correlation coefficient. We systematically study the theoretical properties of the proposed procedure, and establish their sure screening property and the ranking consistency. To enhance the finite sample performance of the proposed procedure, we further develop an iterative feature screening procedure. Monte Carlo simulation studies were conducted to examine the performance of the proposed procedures. In practice, we advocate a two-stage approach for varying coefficient models. The two stage approach consists of (a) reducing the ultrahigh dimensionality by using the proposed procedure and (b) applying regularization methods for dimension-reduced varying coefficient models to make statistical inferences on the coefficient functions. We illustrate the proposed two-stage approach by a real data example.

Cell surface carbohydrates play significant roles in a number of biologically important processes. Heparan sulfate, for instance, is a ubiquitously distributed polysulfated polysaccharide that is involved, among other things, in the initial step of herpes simplex virus type 1 (HSV-1) infection. The virus interacts with cell-surface heparan sulfate to facilitate host-cell attachment and entry. 3-O-Sulfonated heparan sulfate has been found to function as an HSV-1 entry receptor. Achieving a complete understanding of these interactions requires the chemical synthesis of such oligosaccharides, but this remains challenging. Here, we present a convenient approach for the synthesis of two irregular 3-O-sulfonated heparan sulfate octasaccharides, making use of a key disaccharide intermediate to acquire different building blocks for the oligosaccharide chain assembly. Despite substantial structural differences, the prepared 3-O-sulfonated sugars blocked viral infection in a dosage-dependent manner with remarkable similarity to one another.

Interleukin 27 can be used to diagnose TPE in a high prevalence setting, and a negative result can also be reliably used to rule out TPE in all prevalence settings.

We can confirm the positive therapeutic impact and safety to use MARS on liver failure patients with MODS associated with elevated levels of NO and cytokines.