Optical properties of potential-inserted quantum wells in the near infrared and Terahertz ranges

We propose an engineering of the optical properties of GaAs/AlGaAs quantum wells using AlAs and InAs monolayer insertions. A quantitative study of the effects of the monolayer position and the well thickness on the interband and intersubband transitions, based on the extended-basis sp3d5s* tight-binding model, is presented. The effect of insertion on the interband transitions is compared with existing experimental data. As for intersubband transitions, we show that in a GaAs/AlGaAs quantum well including two AlAs and one InAs insertions, a three level {e1 , e2 , e3 } system where the transition energy e3-e2 is lower and the transition energy e2-e1 larger than the longitudinal optical phonon energy (36 meV) can be engineered together with a e3-e2 transition energy widely tunable through the TeraHertz range

Response to Open Peer Commentaries on "Diagnosis By Television Documentary: Professional Responsibilities in Informal Encounters".

In presenting the situation of a health professional witnessing an instance of misdiagnosis and mistreatment in a television documentary, we hoped to stimulate discussion of the professional responsibilities of health workers in informal encounters in a rapidly changing environment comprising print, television, and more recently social media platforms. The commentaries on our article do not disappoint in this respect, providing insightful and sometimes challenging reactions to the position we outlined in response to our original case. In our reply here, we choose to focus on two themes running through all of the commentaries: (1) the distinction between axiological and deontic perspectives invoked by Salloch, and the open-endedness of the former that we see as crucial in addressing the constantly changing media landscape through which health workers may confront medical need; and (2) the role of institutional, structural, and social factors in constraining or enabling virtuous professional practice—suggesting perhaps a further need for health workers to take action directly against structural injustices that prevent them from fulfilling their professional responsibilities

Alternative splicing coupled mRNA decay shapes the temperature‐dependent transcriptome

Mammalian body temperature oscillates with the time of the dayand is altered in diverse pathological conditions. We recently iden-tified a body temperature-sensitive thermometer-like kinase,which alters SR protein phosphorylation and thereby globallycontrols alternative splicing (AS). AS can generate unproductivevariants which are recognized and degraded by diverse mRNAdecay pathways—including nonsense-mediated decay (NMD). Herewe show extensive coupling of body temperature-controlled AS tomRNA decay, leading to global control of temperature-dependentgene expression (GE). Temperature-controlled, decay-inducingsplicing events are evolutionarily conserved and pervasively foundwithin RNA-binding proteins, including most SR proteins. AS-coupledpoison exon inclusion is essential for rhythmic GE of SR proteins andhas a global role in establishing temperature-dependent rhythmicGE profiles, both in mammals under circadian body temperaturecycles and in plants in response to ambient temperature changes.Together, these data identify body temperature-driven AS-coupledmRNA decay as an evolutionary ancient, core clock-independentmechanism to generate rhythmic GE

Isotopic insights into the early Medieval (600-1100 CE) diet in the Luistari cemetery at Eura, Finland

In this article, we present the results of an isotopic study of diet for the early medieval (Merovingian, Viking, Early Christian) humans buried in the unique Luistari cemetery at Eura (ca. 600-1400 CE), southwestern Finland, the largest cemetery of the region. Isotope analysis was conducted on 37 humans for dentine and bone collagen (delta C-13, delta N-15, and delta S-34), and five of them were also studied using compound-specific nitrogen isotope analysis. Dental enamel and/or bone carbonate delta C-13 values were studied from altogether 65 humans, five cattle, and five sheep/goats. The bone and dentine collagen and carbonate data show that throughout the centuries, freshwater fish was a stable part of the diet for the population. Our results do not show systematic dietary differences between estimated males and females, but differences can be large on the individual level. We also discovered a possible temporal change in the enamel carbonate delta C-13 values that could be related to the increasing role of carbohydrates (e.g., crops) in the diet. Luistari burials are well comparable to contemporary Swedish Viking trading communities like Birka in their higher protein intake. But contrary to the wider Viking network, they do not show the same marine signal.Peer reviewe

A multi-factor trafficking site on the spliceosome remodeling enzyme BRR2 recruits C9ORF78 to regulate alternative splicing

The intrinsically unstructured C9ORF78 protein was detected in spliceosomes but its role in splicing is presently unclear. We find that C9ORF78 tightly interacts with the spliceosome remodeling factor, BRR2, in vitro. Affinity purification/mass spectrometry and RNA UV-crosslinking analyses identify additional C9ORF78 interactors in spliceosomes. Cryogenic electron microscopy structures reveal how C9ORF78 and the spliceosomal B complex protein, FBP21, wrap around the C-terminal helicase cassette of BRR2 in a mutually exclusive manner. Knock-down of C9ORF78 leads to alternative NAGNAG 3′-splice site usage and exon skipping, the latter dependent on BRR2. Inspection of spliceosome structures shows that C9ORF78 could contact several detected spliceosome interactors when bound to BRR2, including the suggested 3′-splice site regulating helicase, PRPF22. Together, our data establish C9ORF78 as a late-stage splicing regulatory protein that takes advantage of a multi-factor trafficking site on BRR2, providing one explanation for suggested roles of BRR2 during splicing catalysis and alternative splicing

Magnetic Boron Nitride Nanoribbons with Tunable Electronic Properties

We present theoretical evidence, based on total-energy first-principles calculations, of the existence of spin-polarized states well localized at and extended along the edges of bare zigzag boron nitride nanoribbons. Our calculations predict that all the magnetic configurations studied in this work are thermally accessible at room temperature and present an energy gap. In particular, we show that the high spin state, with a magnetic moment of 1 $\mu_B$ at each edge atom, presents a rich spectrum of electronic behaviors as it can be controlled by applying an external electric field in order to obtain metallic $\leftrightarrow$ semiconducting $\leftrightarrow$ half-metallic transitions.Comment: 12 pages, 5 figures, 2 table

A Snu114-GTP-Prp8 module forms a relay station for efficient splicing in yeast

The single G protein of the spliceosome, Snu114, has been proposed to facilitate splicing as a molecular motor or as a regulatory G protein. However, available structures of spliceosomal complexes show Snu114 in the same GTP-bound state, and presently no Snu114 GTPase-regulatory protein is known. We determined a crystal structure of Snu114 with a Snu114-binding region of the Prp8 protein, in which Snu114 again adopts the same GTP-bound conformation seen in spliceosomes. Snu114 and the Snu114-Prp8 complex co-purified with endogenous GTP. Snu114 exhibited weak, intrinsic GTPase activity that was abolished by the Prp8 Snu114-binding region. Exchange of GTP-contacting residues in Snu114, or of Prp8 residues lining the Snu114 GTP-binding pocket, led to temperature-sensitive yeast growth and affected the same set of splicing events in vivo. Consistent with dynamic Snu114-mediated protein interactions during splicing, our results suggest that the Snu114-GTP-Prp8 module serves as a relay station during spliceosome activation and disassembly, but that GTPase activity may be dispensable for splicing

DDX54 regulates transcriptome dynamics during DNA damage response

The cellular response to genotoxic stress is mediated by a well-characterized network of DNA surveillance pathways. The contribution of posttranscriptional gene regulatory networks to the DNA damage response (DDR) has not been extensively studied. Here, we systematically identified RNA-binding proteins differentially interacting with polyadenylated transcripts upon exposure of human breast carcinoma cells to ionizing radiation (IR). Interestingly, more than 260 proteins including many nucleolar proteins showed increased binding to poly(A) RNA in IR-exposed cells. The functional analysis of DDX54, a candidate genotoxic stress responsive RNA helicase, revealed that this protein is an immediate-to-early DDR regulator required for the splicing efficacy of its target IR-induced pre-mRNAs. Upon IR exposure, DDX54 acts by increased interaction with a well-defined class of pre-mRNAs which harbor introns with weak acceptor splice sites, as well as by protein-protein contacts within components of U2 snRNP and spliceosomal B complex, resulting in lower intron retention and higher processing rates of its target transcripts. Since DDX54 promotes survival after exposure to IR its expression and/or mutation rate may impact DDR-related pathologies. Our work indicates the relevance of many uncharacterized RBPs potentially involved in the DDR