Reactions of the carbonate radical with aliphatic amines

Carbonate radicals react with aliphatic amines by a dual mechanism, viz. (i) hydrogen abstraction and (ii) electron transfer. The former is more probable with primary amines. Tertiary amines react via electron transfer. Both mechanisms may operate in secondary amines. Cyclic tertiary amines react with different rates and their relative reactivities are explained on the basis of the concept of Hoffmann's ‘through bond’ interaction.     

4,4,9,9-Tetraphenyl pyrroloindolizine: a structural analogue of calix[2]pyrrole

Synthesis, spectral and structural characterization of a pyrroloindolizine derivative having structural similarity with calix[2]pyrrole is described. Here, two pyrrole rings are connected with two meso-carbon atoms having an N,α-linkage and an α,β-linkage to afford the smallest analogue in the calixpyrrole family. Detailed NMR spectroscopic studies along with single crystal X-ray analysis confirm the assigned structure of the molecule.     

Probing the Effects of Antimicrobial-Lysozyme Derivatization on Enzymatic Degradation of Poly(ε-caprolactone) Film and Fiber

Surface derivatization is essential for incorporating unique functionalities into biodegradable polymers. Nonetheless, its precise effects on enzymatic biodegradation still lack comprehensive understanding. In this study, a facile solution-based method is employed to surface derivatize poly(ε-caprolactone) films and electrospun fibers with lysozyme, aiming to impart antimicrobial properties and examine the impact on enzymatic degradation. The derivatized films and fibers have shown high antibacterial efficacy against Escherichia coli and Staphylococcus aureus. Through gravimetric analysis, it is observed that the degradation rate experiences a slight decrease upon lysozyme derivatization. However, this reduction is effectively countered by the inclusion of Tween-20, as affirmed by isothermal titration calorimetry. Comparing films and fibers, the latter undergoes degradation at a more accelerated pace, coupled with a rapid decline in molecular weight. This study provides valuable insights into the factors influencing the degradation of surface-derivatized biopolymers through electrospinning, offering a simple strategy to mitigate biomaterial-associated infections.     

Uniform bounds on growth in o‐minimal structures

We prove that a function definable with parameters in an o‐minimal structure is bounded away from ∞ as its argument goes to ∞ by a function definable without parameters, and that this new function can be chosen independently of the parameters in the original function. This generalizes a result in [1]. Moreover, this remains true if the argument is taken to approach any element of the structure (or ±∞), and the function has limit any element of the structure (or ±∞) (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Robust Stability Criteria for Uncertain Neutral Systems with Interval Time-Varying Delay

In this paper, we consider the problem of robust stability of a class of linear uncertain neutral systems with interval time-varying delay under (i) nonlinear perturbations in state, and (ii) time-varying parametric uncertainties using Lyapunov-Krasovskii approach. By constructing a candidate Lyapunov-Krasovskii (LK) functional, that takes into account the delay-range information appropriately, less conservative robust stability criteria are proposed in terms of linear matrix inequalities (LMI) to compute the maximum allowable bound for the delay-range within which the uncertain neutral system under consideration remains asymptotically stable. The reduction in conservatism of the proposed stability criterion over recently reported results is attributed to the fact that time-derivative of the LK functional is bounded tightly without neglecting any useful terms using a minimal number of slack matrix variables. The analysis, subsequently, yields a stability condition in convex LMI framework, that can be solved non-conservatively at boundary conditions using standard LMI solvers. The effectiveness of the proposed stability criterion is demonstrated through standard numerical examples.     

A unified set of proposals for control and design of high speed data networks

In this paper we articulate our philosophy and approach to the design and control of high speed data networks. The object is to put into perspective and to explain the coordination of various isolated pieces of detailed technical analyses that have been reported in several recent papers. In the process we summarize what we have learnt in our recent work and, also, we give indications of the direction of our future work. Our scheme integrates feedback and open loop control. The feedback control is exercised by sliding windows; access controllers regulate bursty sources. All our design proposals are rooted in asymptotic analyses; the justification for asymptotics comes from the largeness of the parameters, such as propagation delay, speed, window size, buffer size, and the number of virtual circuits. This analysis makes a strong case for operating in a specific moderate usage regime, and adaptive dynamic windowing algorithms are given that make this happen; moreover, when in this regime, buffers may be sized aggressively small without jeopardizing performance and the simplicity of the retransmission protocol. The topics in the paper are: model of communication, results on the steady-state behavior of the basic model, access control, small buffers and retransmission protocols, dynamic adaptive windows, bursty sources, and contrast with previous work.I. Mitrani's work was done while AT&T Bell Laboratories.