A series of mono-, di-, tetra- and hexacationic esters of pyropheophorbide a/b have been designed and synthesized to explore the intercalation of their phorbine ring between the base pairs of double-helical DNA and the influence of their peripheral substituents on the DNA interactions. Mono-(1), di-(2, 3) and tetra-(4, 5) cationic pyropheophorbides are soluble as an oligomeric aggregate in HEPE...

We introduce a simple geometric model for a double-stranded and double-helical polymer. We study the statistical mechanics of such polymers using both analytical techniques and simulations. Our model has a single energy scale which determines both the bending and twisting rigidity of the polymer. The helix melts at a particular temperature T(c) below which the chain has a helical structure and ...

Helical double stranded polymers incorporated with a covalently bound chiral ferrocene linker are synthesised and characterized by CD spectra and STM images and molecular dynamics simulations.

α,α′-Di(benzylamino)tripyrrin was synthesized, which exhibited an equilibrium between single- and double-helical forms in solution. XRD analysis showed its co-crystal structure including both forms.

In this article, based on the Euler-Bernoulli beam theory, the large-amplitude vibration of multiwalled carbon nanotubes embedded in an elastic medium is investigated. The method of incremental harmonic balance is implemented to solve the set of governing nonlinear equations coupled via the van der Waals (vdW) interlayer force. The influences of number of tube walls, the elastic medium, nanotub...

The internal working processes in pulse tube cryocooler (PTC) are quite complex due to the unsteady, oscillating compressible gas flow in the pulse tube. Although considerable theoretical studies have been carried out as of date phenomena occurring in a pulse tube cryocooler are still to be understood. The present research work is carried out in order to understand the cooling mechanism and to ...

Rev Esp Cardiol 2002;55(11):1201 1201 A 51-year-old male patient was seen in the emergency room for back pain irradiated to the neck of one week in duration. During the examination, the patient presented hypotension. The electrocardiogram (ECG) showed negative T waves on the inferior face and tall T waves in V1 and V2. In the chest radiograph, mediastinal widening and cardiomegaly were evident....