Search

The Fe²⁺-dependent E. coli enzyme FucO catalyzes the reversible interconversion of short-chain (S)-lactaldehyde and (S)-1,2-propane­diol, using NADH and NAD⁺ as cofactors, respectively. Laboratory-directed evolution experiments have been carried out previously using phenyl­acetaldehyde as the substrate for screening catalytic activity with bulky substrates, which are very poorly reduced by wild-type FucO. These experiments identified the N151G/L259V double mutant (dubbed DA1472) as the most active variant with this substrate via a two-step evolutionary pathway, in which each step consisted of one point mutation. Here the crystal structures of DA1472 and its parent D93 (L259V) are reported, showing that these amino acid substitutions provide more space in the active site, though they do not cause changes in the main-chain conformation. The catalytic activity of DA1472 with the physiological substrate (S)-lactaldehyde and a series of substituted phenyl­acetaldehyde derivatives were systematically quantified and compared with that of wild-type as well as with the corresponding point-mutation variants (N151G and L259V). There is a 9000-fold increase in activity, when expressed as kcat/KM values, for DA1472 compared with wild-type FucO for the phenyl­acetaldehyde substrate. The crystal structure of DA1472 complexed with a non-reactive analog of this substrate (3,4-di­meth­oxy­phenyl­acetamide) suggests the mode of binding of the bulky group of the new substrate. These combined structure–function studies therefore explain the dramatic increase in catalytic activity of the DA1472 variant for bulky aldehyde substrates. The structure comparisons also suggest why the active site in which Fe²⁺ is replaced by Zn²⁺is not able to support catalysis.

A key feature of education systems in German-speaking countries is apprenticeships, dual vocational education and training programmes. These provide students with general human capital and so, a central question is why are firms still willing to invest in these programmes. The theoretical as well as empirical research has consequently been concerned with firms’ costs and benefits of apprenticeship training and the benefits for individuals of taking part in apprenticeships. Recent research has looked at more general benefits of apprenticeships, such as innovation, adaption to technical change and lifelong learning.

As 5G New Radio (NR) is being rolled out, research effort is being focused on the evolution of what is to come in the post-5G era. In order to meet the diverse requirements of future wireless communication in terms of increased capacity and reduced latency, technologies such as distributed massive Multiple-Input Multiple-Output (MIMO), sub-millimeter wave and Tera-hertz spectrum become technology components of interest. Furthermore, to meet the demands on connectivity anywhere at anytime, non-terrestrial satellite networks will be needed, which brings about challenges both in terms of implementation as well as deployment. Finally, scaling up massive Internet-of-Things (IoT), energy harvesting and Simultaneous Wireless Information and Power Transfer (SWIPT) is foreseen to become important enablers when deploying a large amount of small, low-power radios. In this paper, we will discuss some of the important opportunities these technologies bring, and the challenges faced by the microwave and wireless communication communities.

Across many industries, individuals are increasingly relying on customer ratings and reviews on social media. While customer reviews often provide detailed diagnostic information about experiences, customer ratings often reduce the experience down to a simple number. Moreover, there is evidence to support that customer rating inflation is occurring on social media sites over time, especially in the sharing economy, and especially with regard to travel and tourism experiences. This paper conceptualizes how customer experiences are reduced into customer reviews and further abridged into customer ratings in both the traditional and sharing economy contexts. We propose that customers observe how service providers present themselves as a professional (established chain hotel) or amateur (owner operated vacation rental apartment), and then form different service expectations and perceptions accordingly. We investigate 55,110 customer reviews and ratings of New York City’s accommodation providers and indeed find evidence of rating inflation over the eight years studied., QC 20201210

Anatomical stature estimation methods reconstruct stature for skeletal specimens by adding up the heights of skeletal elements contributing to stature. In addition, these estimations factor in a certain amount of soft tissue known as “soft tissue correction”. Our study focuses on the relationship between living stature and one of the major soft tissue contributors to stature: the intervertebral disc thickness/height. The purpose of this study was to clarify whether intervertebral disc thickness is greater in tall individuals and whether there is a linear correlation between stature and intervertebral disc height. To conduct this study, we utilized a subsample of the Northern Finland Birth Cohort of 1966 (n = 12,058) with known stature. We measured vertebral heights and intervertebral disc heights from low back MRI examination performed at the age of 46 years (n = 200). All subjects were considered healthy with no spinal injuries or pathologies. Our results clearly indicate that stature and intervertebral disc height have positive, statistically significant association. According to our results it is advisable to take into account the individual’s skeletal height when soft tissue corrections for anatomical stature estimations are performed. Further studies utilizing full body MRI are needed to produce more accurate soft tissue corrections.