Structure and function of Escherichia coli valine transfer RNA in aminoacylation and ternary complex formation

The relationship of E. coli tRNA Val structure to its function in the aminoacylation reaction and the later steps of polypeptide synthesis was investigated. Steady-state kinetic studies of the aminoacylation of invitro transcribed tRNA Val variants have shown that nucleotides, A35, C36, A73, and G20, are important for the specific recognition of E. coli tRNA Val by valyl-tRNA synthetase (ValRS). Identity swap experiments, testing the efficiency of this recognition nucleotide set in converting yeast tRNA Phe and E. coli tRNA Phe into caline acceptors, confirm the importance of the recognition nucleotide set. In addition, a minor recognition nucleotide, G45, was also identified. Furthermore, our results indicate that ValRS requires an undistorted A-form helix in the acceptor stem for efficient aminoacylation of the tRNA substrate;In a study of the universally conserved 3\u27-CCA sequence of tRNA Val, our laboratory has shown that the 3\u27-CCA is not essential for all functions. Substitution of the usual 3\u27-terminal adenine with either cytosine or uracil yields tRNA Val that readily accepts valine. Although tRNA Val with a terminal guanine can be fully aminoacylated, it is a much poorer substrate for ValRS. The tRNA Val variant terminating with G is, however, fully active in polypeptide synthesis whereas the C and U variants are inactive. Recent results, showing that pyrimidine (C or U) substitution at the 3\u27-terminal position of tRNA Val significantly reduces the ability of valyl-tRNA Val to form a ternary complex with EF-Tu and GTP, explain the inability of these tRNA Val variants to transfer valine into polypeptides. tRNA Val terminating with 3\u27-G forms a ternary complex quite readily. Dissociation constants of ternary complexes involving U and C substituted valyl-tRNA Val are one and two orders of magnitude larger, respectively, than that of ternary complex with wild-type valyl-tRNA val. Similar results are also observed in the interaction of E. coli tRNA Ala and tRNA Phe with EF-Tu:GTP. These results suggest that interaction of EF-Tu:GTP with aminoacyl-tRNA involves specific recognition of a purine at the 3\u27-terminus of tRNA

Paid content strategies for news websites: An empirical study of British newspapers' online business models

This study uses qualitative research interviews and a survey to quantify and analyse business models at online newspapers in the UK. Senior editors and executives reported that news websites rely on advertising income to a greater extent than their print counterparts. Despite this, British news sites continue to charge users for some content, although to a varying degree. The fact that online editions still contribute barely a tenth of total revenues explains this experimental approach towards business strategy. Although paid-for content has mostly failed as a mechanism for the online news business in the past, changes in technology and net culture may mean that it is becoming an option again. The authors examine what content is being charged for and why, and investigate: how the 12 newspapers studied are balancing the need to develop additional revenue streams with the demand for traffic in a buoyant advertising market; the extent to which cannibalisation of the print parent is still a concern; the complementary benefits of developing digital products; strategies towards archived content; the value of columnist content to online users; the success of digital editions and email alerts; the potential of mobile services; and the rapidly developing number of online services and commercial partnerships hosted by newspapers on the Web

106GBaud (200G PAM4) CWDM EML for 800G/1.6T Optical Networks and AI Applications

We report ultrahigh speed 106GBaud (200G PAM4) electro-absorption modulated laser (EML) for 800G and 1.6T optical transmission. Four CWDM EMLs of 1271, 1291, 1311 and 1331nm in 800G FR4 optical transceivers show clear eye diagram after 2km. Our 106GBaud EMLs show high bandwidth, high extinction ratio, low threshold current and high power, making it a suitable source laser for 800G/1.6T and AI applications.&nbsp

Exploring Individuals’ Loyalty To Online Support Groups From the Perspective Of Social Support

Prior research indicates that social support allows individuals to have additional skills to handle stresses, enhance self-esteem, and increase psychological well-being. Online social networks have become an emerging and important source of social support. However, little research has been done to explore how IT usage may improve the well-being and life quality of individuals, especially patients. Little research has been done to empirically examine individuals’ loyalty toward online social groups from the perspective of social support. This study aims to develop an integrated research model to the impact of online social support on psychological well-being and group identification, and individuals’ subsequent loyalty toward online social groups. Online social support group was operationalized as a second-order construct with four components: informational, emotional, esteem, and network supports. Data collected from 537 users of online support groups for mothers in Taiwan provide strong support for the research model. The results indicate that online social support is positively associated with psychological well-being and group identification, which in turn have a positive effect on moms’ loyalty toward online social groups. Implications for theory and practice and suggestions for future research are provided

Highly Facet-reflection Immune 53GBaud EML for 800G Artificial Intelligence Optical Transceivers

We developed a facet-reflection immune 53GBaud electro-absorption modulated laser (EML) for 800G artificial intelligence (AI) optical network. An ultra-low anti-reflection (AR) coating reflectivity of 2x10-5 has been demonstrated for straight waveguide. Based on Hakki-Paoli method, we characterized the ultra-low AR using the ripple test technique. Such ultra-low AR is critical in achieving excellent eye pattern and optical transmission for 800G AI supercomputing

Synergies between interstellar dust and heliospheric science with an Interstellar Probe

We discuss the synergies between heliospheric and dust science, the open science questions, the technological endeavors and programmatic aspects that are important to maintain or develop in the decade to come. In particular, we illustrate how we can use interstellar dust in the solar system as a tracer for the (dynamic) heliosphere properties, and emphasize the fairly unexplored, but potentially important science question of the role of cosmic dust in heliospheric and astrospheric physics. We show that an Interstellar Probe mission with a dedicated dust suite would bring unprecedented advances to interstellar dust research, and can also contribute-through measuring dust - to heliospheric science. This can, in particular, be done well if we work in synergy with other missions inside the solar system, thereby using multiple vantage points in space to measure the dust as it `rolls' into the heliosphere. Such synergies between missions inside the solar system and far out are crucial for disentangling the spatially and temporally varying dust flow. Finally, we highlight the relevant instrumentation and its suitability for contributing to finding answers to the research questions.Comment: 18 pages, 7 Figures, 5 Tables. Originally submitted as white paper for the National Academies Decadal Survey for Solar and Space Physics 2024-203

Focused wave interactions with floating structures: A blind comparative study

The paper presents results from the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) Blind Test Series 2. Without prior access to the physical data, participants, with numerical methods ranging from low-fidelity linear models to fully non-linear Navier−Stokes (NS) solvers, simulate the interaction between focused wave events and two separate, taut-moored, floating structures: a hemispherical-bottomed cylinder and a cylinder with a moonpool. The ‘blind’ numerical predictions for heave, surge, pitch and mooring load, are compared against physical measurements. Dynamic time warping is used to quantify the predictive capability of participating methods. In general, NS solvers and hybrid methods give more accurate predictions; however, heave amplitude is predicted reasonably well by all methods; and a WEC-Sim implementation, with CFD-informed viscous terms, demonstrates comparable predictive capability to even the stronger NS solvers. Large variations in the solutions are observed (even among similar methods), highlighting a need for standardisation in the numerical modelling of WSI problems

Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe