The Synthesis of Vicinal Diacylamines via Bamberger Ring Cleavage of Substituted Imidazoles. 1,2,4-Triacylaminobutanes Bearing Different Acyl Groups

Bamberger ring cleavage acylation of N-p-toluenesulfonyl (tosyl) histamine followed by hydrogenation yields 3,4-diacylaminobutanetosylamine, a triamine containing groups with different chemical reactivities.     

Lower bounds for multivariate approximation by affine-invariantdictionaries

The problem of approximating locally smooth multivariate functions by linear combinations of elements from an affine-invariant redundant dictionary is considered. Augmenting previous upper bound results for approximation, we establish lower bounds on the performance of such schemes. The lower bounds are tight to within a logarithmic factor in the number of elements used in the approximation. Using a previously introduced notion of nonlinear approximation, we show that the approximation ability may be completely characterized by the pseudodimension of the approximation space with respect to a finite set of points. This result establishes a useful link between the problems of approximation and estimation, or learning, the latter often being conveniently characterized, at least in terms of upper bounds, by the pseudodimension     

A Comparative Study of Continuous and Periodic Inspection Policies in Deteriorating Production Systems

Continuous or periodic inspection policies are often used to monitor the maintenance of a production process. In this paper, a comparative study of continuous and periodic inspection policies in deteriorating production systems is provided. The overall cost function is comprised of: set-up, inspection, inventory holding, defective and restoration costs. Different models, constant, linear and exponential, of restoration costs are considered. Tradeoffs between the continuous and the periodic inspection policies are analyzed, and ranges of values of system or cost parameters for which the continuous inspection policy is preferred are established.     

Thermal performance of combined solar systems with different collector efficiencies

The performance of two kinds of solar systems for space- and domestic hot water heating has been compared by computer simulations. One system is a conventional radiator-based heating system with collectors of ‘ideal’ collector coefficients. The second system is a low temperature heating system with solar collectors of moderate efficiency. The investigation shows that the difference in performance of the two systems is in the order of 1–6%.     

Assessing cellular toxicities in fibroblasts upon exposure to lipid-based nanoparticles: a high content analysis approach

Lipid-based nanoparticles (LNPs) are widely used for the delivery of drugs and nucleic acids. Although most of them are considered safe, there is confusing evidence in the literature regarding their potential cellular toxicities. Moreover, little is known about the recovery process cells undergo after a cytotoxic insult. We have previously studied the systemic effects of common LNPs with different surface charge (cationic, anionic, neutral) and revealed that positively charged LNPs ((+)LNPs) activate pro-inflammatory cytokines and induce interferon response by acting as an agonist of Toll-like receptor 4 on immune cells. In this study, we focused on the response of human fibroblasts exposed to LNPs and their cellular recovery process. To this end, we used image-based high content analysis (HCA). Using this strategy, we were able to show simultaneously, in several intracellular parameters, that fibroblasts can recover from the cytotoxic effects of (+)LNPs. The use of HCA opens new avenues in understanding cellular response and nanotoxicity and may become a valuable tool for screening safe materials for drug delivery and tissue engineering.