Unraveling the complex polymorphic crystallization behavior of the alternating copolymer DMDS-alt-DVE

[Abstract]: A complex crystallization behavior was observe the alternating copolymer DMDS-alt-step-growth polymerization. Understanding the underlying complex crystallization processes of such innovative polythioethers is critical for their application, for example, in polymer coating technologies. These alternating copolymers have polymorphic traits, resulting in different phases that may display distinct crystalline structures. The copolymer DMDS-alt-DVE was studied in an earlier work, where only two crystalline phases were reported: a low melting, L − Tm, and high melting, H − Tm phase. Remarkably, the H − Tm form was only achieved by the previous formation and melting of the L − Tm form. We applied calorimetric techniques encompassing seven orders of magnitude in scanning rates to further explore this complex polymorphic behavior. Most importantly, by rapidly quenching the sample to temperatures well below room temperature, we detected an additional polymorphic form (characterized by a very low melting phase, denoted VL − Tm). Moreover, through tailored thermal protocols, we successfully produced samples containing only one, two, or all three polymorphs, providing insights into their interrelationships. Understanding polymorphism, crystallization, and esulting morphological differences can have significant implications and potential impact on mechanical resistance and barrier roperties.Gobierno Vasco; IT1503-22Gobierno Vasco; IT-1525-22Ministerio de Ciencia e Innovación; PGC2018-094620-A-I00Xunta de Galicia; ED431F 2021/00

Spin dynamics in semiconductors

This article reviews the current status of spin dynamics in semiconductors which has achieved a lot of progress in the past years due to the fast growing field of semiconductor spintronics. The primary focus is the theoretical and experimental developments of spin relaxation and dephasing in both spin precession in time domain and spin diffusion and transport in spacial domain. A fully microscopic many-body investigation on spin dynamics based on the kinetic spin Bloch equation approach is reviewed comprehensively.Comment: a review article with 193 pages and 1103 references. To be published in Physics Reports

An innovative method to study target protein-drug interactions by mass spectrometry

We report the combination of chemical cross-linking and high-resolution mass spectrometry for analyzing conformational changes in target proteins that are induced by drug binding. With this approach conformational changes in the peroxisome proliferator-activated receptor alpha (PPARα) upon binding of low-molecular weight compounds were readily detected, proving that the strategy provides a basis to efficiently characterize target protein−drug interactions

Cnidarian gene expression patterns and the origins of bilaterality – are cnidarians reading the same game plan as "higher" animals?

[Extract] The past few years have seen a dramatic increase in the available data on gene sequence and gene expression for cnidarians and other "lower" Metazoa, and a flurry of recent papers has drawn on these to address the origins of bilaterality. Cnidarianhomologs of many genes that play key roles in the specification of both the A/P and D/V axes of bilaterians have been characterized, and their patterns of expression determined. Some of these expression patterns are consistent with the conservation of function between Cnidaria and Bilateria, but others clearly differ. Moreover, in some cases very different interpretations have been made on the basis of the same, or similar,\ud data. In part, these differences reflect the inevitable uncertainties associated with the depth of the divergence between cnidarians and bilaterians. In this paper we briefly summarize the cnidarian data on gene expression\ud and organization relevant to axis formation, the varying interpretations of these data, and where they conflict. Our conclusion is that the oral-aboral axis probably does correspond to the anterior-posterior axis of bilaterians,\ud but that its polarity remains uncertain, and that many of the same genes are involved in determining the directive axis of cnidarians and the dorsal-ventral axis of bilaterians, but with sufficient differences in expression that exact homologies are uncertain