Communication In Complex Research Articles

Reconfigurable Tri-Mode Metasurface for Broadband Low Observation, Wide-Range Tracing, and Backscatter Communication.

In the current prevalent complex electromagnetic (EM) environment, intelligent methods for versatile and integrated control of EM waves using compact devices are both essential and challenging. These varied wave control objectives can at times conflict with one another, such as the need for broad absorption to remain inconspicuous, while also requiring enhanced backward scattering for highly reliable tracing and secure communication. To address these sophisticated challenges, a microwave-frequency reconfigurable tri-mode metasurface (RTMM) is introduced. The proposed innovation enables three distinct operational modes: broadband low observation, enhanced EM wave tracing, and backscatter communication over a wide-angle range by simple control of the PIN diodes embedded in each meta-atom. The proof-of-concept demonstration of the fabricated prototype verified the switchable tri-mode performance of the RTMM. This proposed RTMM can be adapted to various applications, including EM shielding, target detection, and secure communication in complex and threatening EM environments, paving the way for environmentally-adaptive EM wave manipulation.

Biogeography and the evolution of acoustic communication in the polyploid North American grey treefrog complex.

After polyploid species are formed, interactions between diploid and polyploid lineages may generate additional diversity in novel cytotypes and phenotypes. In anurans, mate choice by acoustic communication is the primary method by which individuals identify their own species and assess suitable mates. As such, the evolution of acoustic signals is an important mechanism for contributing to reproductive isolation and diversification in this group. Here, we estimate the biogeographical history of the North American grey treefrog complex, consisting of the diploid Hyla chrysoscelis and the tetraploid Hyla versicolor, focusing specifically on the geographical origin of whole genome duplication and the expansion of lineages out of glacial refugia. We then test for lineage-specific differences in mating signals by applying comparative methods to a large acoustic data set collected over 52 years that includes >1500 individual frogs. Along with describing the overall biogeographical history and call diversity, we found evidence that the geographical origin of H. versicolor and the formation of the midwestern polyploid lineage are both associated with glacial limits, and that the southwestern polyploid lineage is associated with a shift in acoustic phenotype relative to the diploid lineage with which they share a mitochondrial lineage. In H. chrysoscelis, we see that acoustic signals are largely split by Eastern and Western lineages, but that northward expansion along either side of the Appalachian Mountains is associated with further acoustic diversification. Overall, results of this study provide substantial clarity on the evolution of grey treefrogs as it relates to their biogeography and acoustic communication.

Electromechanical Coupling and Application of High-Frequency Communication Antenna Channel Capacity

The next-generation communication base station antennas represented by phased array antennas are towards high frequency, high gain, high density, and high pointing accuracy. The influence of mechanical structure factors on communication system channel quality is obviously increasing, and the electromechanical coupling problem is becoming more prominent. To effectively guarantee the realization of 5G/6G communication in complex working environments and accelerate the commercial process of future communication systems, an electromechanical coupling channel capacity model is established in comprehensive consideration of the positional shift, attitude deflection, and temperature change of the communication base station phased array antennas. It can be used to rapidly evaluate the communication index degradation of RF devices within the heating environment. Moreover, a sensitivity model of the electric field strength and array antenna channel capacity to the random position error of each element is constructed. The influence of the random positioning error of each element on the communication indicators is analyzed and compared under different working conditions. The simulation results show that the proposed model can effectively provide a theoretical basis and guiding role for the design and manufacture of high-frequency array base station antennas.

Link Redundancy Research and Reliability Analysis Based on Dual CAN Architecture

Aiming at the problem that special vehicles still need to ensure the reliability of vehicle-mounted bus communication in the long-term complex and strong interference communication environment, a link layer redundancy scheme based on dual CAN channels is proposed. By adding redundant modules and improving the redundancy mechanism, dual CAN controllers can not only realize the undisturbed switching of data communication in hot redundancy mode, but also realize the function of error correction and retransmission in cold redundancy mode. Finally, a mathematical model of the reliability of dual CAN redundancy is established through the Markov state transfer chain, and this model is compared with other models for analysis and evaluation to verify that its reliability is significantly improved.

Dynamics and structural communication in the ternary complex of fully phosphorylated V2 vasopressin receptor, vasopressin, and β-arrestin 1

G protein-coupled receptors (GPCRs) are critically regulated by arrestins, which not only desensitize G-protein signaling but also initiate a G protein-independent wave of signaling.The information from structure determination was herein exploited to build a structural model of the ternary complex, comprising fully phosphorylated V2 vasopressin receptor (V2R), the agonist arginine vasopressin (AVP), and β-arrestin 1 (β-arr1). Molecular simulations served to explore dynamics and structural communication in the ternary complex.Flexibility and mechanical profiles reflect fold of V2R and β-arr1. Highly conserved amino acids tend to behave as hubs in the structure network and contribute the most to the mechanical rigidity of V2R seven-helix bundle and of β-arr1. Two structurally and dynamically distinct receptor-arrestin interfaces assist the twist of the N- and C-terminal domains (ND and CD, respectively) of β-arr1 with respect to each other, which is linked to arrestin activation. While motion of the ND is essentially assisted by the fully phosphorylated C-tail of V2R (V2RCt), that of CD is assisted by the second and third intracellular loops and the cytosolic extensions of helices 5 and 6. In the presence of the receptor, the β-arr1 inter-domain twist angle correlates with the modes describing the essential subspace of the ternary complex. β-arr1 motions are also influenced by the anchoring to the membrane of the C-edge-loops in the β-arr1-CD. Overall fluctuations reveal a coupling between motions of the agonist binding site and of β-arr1-ND, which are in allosteric communication between each other. Mechanical rigidity points, often acting as hubs in the structure network and distributed along the main axis of the receptor helix bundle, contribute to establish a preferential communication pathway between agonist ligand and the ND of arrestin. Such communication, mediated by highly conserved amino acids, involves also the first amino acid in the arrestin C-tail, which is highly dynamic and is involved in clathrin-mediated GPCR internalization.

Analysis of allosteric communication in a multienzyme complex by ancestral sequence reconstruction.

Tryptophan synthase (TS) is a heterotetrameric αββα complex. It is characterized by the channeling of the reaction intermediate indole and the mutual activation of the α-subunit TrpA and the β-subunit TrpB via a complex allosteric network. We have analyzed this allosteric network by means of ancestral sequence reconstruction (ASR), which is an in silico method to resurrect extinct ancestors of modern proteins. Previously, the sequences of TrpA and TrpB from the last bacterial common ancestor (LBCA) have been computed by means of ASR and characterized. LBCA-TS is similar to modern TS by forming a αββα complex with indole channeling taking place. However, LBCA-TrpA allosterically decreases the activity of LBCA-TrpB, whereas, for example, the modern ncTrpA from Neptuniibacter caesariensis allosterically increases the activity of ncTrpB. To identify amino acid residues that are responsible for this inversion of the allosteric effect, all 6 evolutionary TrpA and TrpB intermediates that stepwise link LBCA-TS with ncTS were characterized. Remarkably, the switching from TrpB inhibition to TrpB activation by TrpA occurred between 2 successive TS intermediates. Sequence comparison of these 2 intermediates and iterative rounds of site-directed mutagenesis allowed us to identify 4 of 413 residues from TrpB that are crucial for its allosteric activation by TrpA. The effect of our mutational studies was rationalized by a community analysis based on molecular dynamics simulations. Our findings demonstrate that ancestral sequence reconstruction can efficiently identify residues contributing to allosteric signal propagation in multienzyme complexes.

New perspectives on substituted relational autonomy for shared decision-making in critical care

In critical care when unconscious patients are assisted by machines, humanity is mainly ensured by respect for autonomy, realised through advance directives or, mostly, reconstructed by cooperation with relatives. Whereas patient-centred approaches are widely discussed and fostered, managing communication in complex, especially end-of-life, situations in open intensive care units is still a point of debate and a possible source of conflict and moral distress. In particular, healthcare teams are often sceptical about the growing role of families in shared decision-making and their ability to represent patients’ preferences. New perspectives on substituted relational autonomy are needed for overcoming this climate of suspicion and are discussed through recent literature in the field of medical ethics.

Speech-in-noise research: From classrooms to Canadian Armed Forces operational environments

The importance of speech intelligibility in learning and occupational environments is evidenced by the abundance of research in room acoustics and auditory communication. In addition to environmental factors such as background noise and reverberation, individual factors including the presence of hearing loss, wearing of hearing aids and hearing protection devices (HPDs), and language proficiency must be considered. Previous work in these areas has provided a benchmark for the study of communication in complex, high noise environments. For Canadian Armed Forces (CAF) members, the high noise levels inside aircraft, armoured vehicles and sea vessels demand the use of HPDs and integrated radio communication systems. This presentation will summarize our research on speech understanding in noise and multi-talker environments using different communication headsets, simulated hearing loss and language proficiency. We will focus on our recent studies of communication between native (L1) and non-native (L2) English speakers, which is applicable to the CAF due to the relatively high percentage of L2 membership. L2 speakers obtained lower scores on speech-in-noise tests than L1 speakers for both radioed and face-to-face speech, despite having a high level of language proficiency. Preliminary results of an investigation of cognitive load for L2 listeners will also be presented.

Overseas Qualified Nurses’ (OQNs) perspectives and experiences of intraprofessional and nurse-patient communication through a Community of Practice lens

BackgroundOverseas qualified nurses enter their new workplaces as experienced newcomers, who are challenged by unfamiliar patterns of communication with patients and colleagues. Little is known of the relational dimension of these nurses’ adjustment to unfamiliar communication norms. AimThis paper explores the barriers and enablers of clinical communication experiences of OQNs from their perspective using a Communities of Practice framework. MethodsThis exploratory qualitative study involved semi-structured interviews of OQNs (males=4, females=17) employed in acute and semi-acute clinical settings, at a major metropolitan hospital in Melbourne, Australia, with a increased OQN presence. Verbatim transcripts were analysed using thematic analysis. FindingsTwo major themes emerged from the analysis. The first theme comprised the pre-existing attributes of self, as both a barriers and enabler with sub themes of language adaptability and preparedness. The second theme was interactions with colleagues and patients with sub themes of expectations, adjustment and career progression. As seen through the CoP lens, these themes had a relational dimension, as communication with other staff and patients reportedly impacted on the nurses’ development in an unfamiliar healthcare environment. ConclusionOQNs can find communication in Australian healthcare complex and challenging making it an important area for learning. Intercultural communication issues stand out as a crucial factor in these nurses’ transitions. ‘Newcomer’ OQNs need active and meaningful interactions with local colleagues (old timers) and patients in order to gain language and cultural understanding of the new context. Provision of an ongoing supportive learning environment with opportunities for constructive feedback will help OQNs move from peripheral participation to full participation in health care encounters.

Sensitizing the Photocatalytic Ability of Dawson-Wells Polyoxometalates in Solution and Thin Films

Heteropolyoxomolybdate anions exhibit rich redox and photochemistry enabled by the capacity of polyoxomolybdate to act as both electron and proton relays. They are widely investigated for application across domains involving photooxidation and photocatalysis. A key limitation though is that polyoxometallates such as [S2M18O62]4-, where M is W or Mo, are not signifantly activated by visible light. This presentation describes investigations into the sensitization of Dawson polyoxometallates photochemistry [S2Mo18O62]4- and [S2W18O62]4- by ruthenium(II)polypyridine complexes in solution and at modified electrodes. Electrostatically associated supramolecular structures comprising of ruthenium polypyridyl cations and polyoxoanions can be readily isolated as charge neutral adducts by combining the cation and anion in solution. For [Ru(bpy)3]2+ with [S2Mo18O62]4- or [S2W18O62]4- the polyoxometallate adducts are remarkably photostable. And [Ru(bpy)3]2+ the resulting clusters sensitises the very efficient photooxidation of organic substrates such as DMF and benzylalcohol by the polyoxometalates under visible irradiation, between 355 and 490 nm.. Resonance Raman spectroscopy was used to identify a charge transfer transition between Ru and polyoxometallate which suggests significant electronic communication in these cluster complex. Exploiting resonance Raman spectroscopy to identify the presence of the CT transition we took a combinatorial approach to identifying potentially sensitized Ru(II)-POM pairs and assemble the resulting pairs into layer by layer electrostatic assemblies at electrodes. The photoelectrochemical response of these systems, with a range of organic donors, including persistent pollutants diclofenac and ibuprofen is described. References Nigel Fay, Victoria M. Hultgren, Anthony G. Wedd, Tia E. Keyes, Deirdre Leane, Alan M. Bond, Dalton Trans, 2006, 4218 - 4227.Visible Light Sensitized Photocurrent Generation from Electrostatically Assembled Thin Films of [Ru(bpy)3]2+ and the polyoxometalate [W18O54(SO4)2]4-; Optimizing Performance in a low electrolyte media, James J Walsh; Jie Zhu; Alan M Bond; Robert J Forster, Tia E Keyes, 2013, Journal of Electroanal. Chem., 2013, 706, 93-101Hybrid Polyoxometalate Materials for Photo(electro-) chemical Applications., J. Walsh, A.M. Bond, R.J. Forster, T.E. Keyes, Coord. Chem Rev., Volume 306, Part 1, 1 January 2016, Pages 217–234 Figure 1

Anion-regulated electronic communication in a cyclometalated diruthenium complex with a urea bridge.

A combined study of electrochemical measurements, intervalence charge transfer analysis, and DFT calculations suggests that the degree of urea-mediated electronic coupling between two cyclometalated ruthenium sites is enhanced by the coordination of urea with Br- or Cl-via hydrogen bonding. In contrast, the redox waves of the diruthenium complex become highly irreversible in the presence of relatively strong basic anions such as H2PO4-, F-, or OAc-. This work demonstrates that the anion-urea interaction can be employed to regulate the electronic coupling and electron transfer between redox-active sites, suggesting the potential applications of the urea-functionalized diruthenium complex in anion sensing and stimuli-responsive molecular electronics.

Internal switches modulating electron tunneling currents in respiratory complex III

In different X-ray crystal structures of bc1 complex, some of the key residues of electron tunneling pathways are observed in different conformations; here we examine their relative importance in modulating electron transfer and propose their possible gating function in the Q-cycle. The study includes inter-monomeric electron transfer; here we provide atomistic details of the reaction, and discuss the possible roles of inter-monomeric electronic communication in bc1 complex. Binding of natural ligands or inhibitors leads to local conformational changes which propagate through protein and control the conformation of key residues involved in the electron tunneling pathways. Aromatic–aromatic interactions are highly utilized in the communication network since the key residues are aromatic in nature. The calculations show that there is a substantial change of the electron transfer rates between different redox pairs depending on the different conformations acquired by the key residues of the complex.

Postcultural Communication? – Intercultural communication from a postcultural position

When we as scholars use the concept of intercultural communication in its classic definition, as communication between people with different cultural backgrounds, we perpetuate the notion that national differences influence communication more than other differences; in doing so, ethnic minorities in multicultural societies are silently/verbally excluded from national communities. The aim of the article is to develop a theoretical position, which is able to conceptualize intercultural communication in complex multicultural societies and function as a frame for empirical analysis. The theoretical position is presented as a postcultural prism composed by practice theory (Schatzki 1996, Reckwitz 2002, Nicolini 2012, Kemmis 2012), Intersectionality (Brah, Phoenix, Collins Rahsack) and positioning theory (Harre & Langenhove 1998).

Pyrene-Based Mono- and Di-N-Heterocyclic Carbene Ligand Complexes of Ruthenium for the Preparation of Mixed Arylated/Alkylated Arylpyridines

By using two pyrene-based mono- and di-N-heterocyclic carbene ligands, two ruthenium complexes (one monometallic and the other dimetallic) have been obtained and fully characterized. The molecular structure of the dimetallic complex has been determined by means of X-ray diffraction studies. The electrochemical studies reveal that the metal–metal communication in the dimetallic complex is weak. The catalytic activity of both complexes has been tested in the arylation of arylpyridines with aryl halides and in the hydroarylation of alkenes, where they showed similar activity. The sequential combination of these two catalytic processes (hydroarylation of alkenes followed by arylation of the resulting alkyl-substituted arylpyridine) allowed the preparation of mixed arylated/alkylated arylpyridines. In this tandem process, the dimetallic complex afforded activity higher than that of the monometallic complex. The activity was compared to that shown by the [RuCl2(p-cymene)]2 complex. This reaction constitutes an ...

The Tryptophan Synthase α2β2 Complex: A Model for Substrate Channeling, Allosteric Communication, and Pyridoxal Phosphate Catalysis

I reflect on my research on pyridoxal phosphate (PLP) enzymes over fifty-five years and on how I combined research with marriage and family. My Ph.D. research with Esmond E. Snell established one aspect of PLP enzyme mechanism. My postdoctoral work first with Hans L. Kornberg and then with Alton Meister characterized the structure and function of another PLP enzyme, l-aspartate β-decarboxylase. My independent research at the National Institutes of Health (NIH) since 1966 has focused on the bacterial tryptophan synthase α2β2 complex. The β subunit catalyzes a number of PLP-dependent reactions. We have characterized these reactions and the allosteric effects of the α subunit. We also used chemical modification to probe enzyme structure and function. Our crystallization of the tryptophan synthase α2β2 complex from Salmonella typhimurium led to the determination of the three-dimensional structure with Craig Hyde and David Davies at NIH in 1988. This landmark structure was the first structure of a multienzyme complex and the first structure revealing an intramolecular tunnel. The structure has provided a basis for exploring mechanisms of catalysis, channeling, and allosteric communication in the tryptophan synthase α2β2 complex. The structure serves as a model for many other multiprotein complexes that are important for biological processes in prokaryotes and eukaryotes.

Inter- and Intra-Monomeric Communication in the Cytochrome Bc1 Complex: A Molecular Dynamics Study

The cytochrome bc1 complex (bc1) is a widespread, dimeric redox-driven proton translocase. It oxidizes molecules of ubiquinol (UQH2) in the site QP of the cytochrome b subunit, whereby the two released electrons are transferred, respectively, to the heme of cytochrome c1 - via the mobile soluble domain of the Rieske protein (the “head” domain) - and to a ubiquinone (UQ) molecule in the QN site of cytochrome b.Earlier kinetic studies have indicated that the movement of the Rieske “head” domain could be coupled with the quinone reduction in the QN site. Thermodynamics considerations also indicate that the ability of the Rieske “head” domain in one monomer to move towards cytochrome c1 might be coupled with the docking of the “head” domain to cytochrome b in the other monomer. However, the details of such mechanistic coupling within the bc1 dimer remain elusive.In the present study, large-scale MD simulations were used to track the communications within the bc1 of Rhodobacter sphaeroides.Different computational techniques (correlation analysis of interaction energies, motion cross-correlation, co-evolution of amino acid positions) have revealed possible pathways for transmembrane propagation of information about the redox state of UQ in the QN site. Equilibrium and metadynamics simulations of the bc1 revealed two distinct binding modes for semiquinone (SQ) and UQH2/UQ in the QN site and the two positions of UQ in the QP site which corresponded to these QN modes, whereby a SQ in the QN site favored tighter docking of the Rieske “head” domain and hindered its outward motion. Metadynamics simulations also showed that the Rieske “head” domain of one bc1 monomer could easier move towards cytochrome c1 when the “head” domain in the opposite monomer was docked to cytochrome b.

Inter- and intra-monomeric communication in the cytochrome bc1 complex as studied by molecular dynamics simulations

Inter- and intra-monomeric communication in the cytochrome bc1 complex as studied by molecular dynamics simulations

Preattentive Extraction of Abstract Auditory Rules in Speech Sound Stream: A Mismatch Negativity Study Using Lexical Tones

BackgroundExtraction of linguistically relevant auditory features is critical for speech comprehension in complex auditory environments, in which the relationships between acoustic stimuli are often abstract and constant while the stimuli per se are varying. These relationships are referred to as the abstract auditory rule in speech and have been investigated for their underlying neural mechanisms at an attentive stage. However, the issue of whether or not there is a sensory intelligence that enables one to automatically encode abstract auditory rules in speech at a preattentive stage has not yet been thoroughly addressed.Methodology/Principal FindingsWe chose Chinese lexical tones for the current study because they help to define word meaning and hence facilitate the fabrication of an abstract auditory rule in a speech sound stream. We continuously presented native Chinese speakers with Chinese vowels differing in formant, intensity, and level of pitch to construct a complex and varying auditory stream. In this stream, most of the sounds shared flat lexical tones to form an embedded abstract auditory rule. Occasionally the rule was randomly violated by those with a rising or falling lexical tone. The results showed that the violation of the abstract auditory rule of lexical tones evoked a robust preattentive auditory response, as revealed by whole-head electrical recordings of the mismatch negativity (MMN), though none of the subjects acquired explicit knowledge of the rule or became aware of the violation.Conclusions/SignificanceOur results demonstrate that there is an auditory sensory intelligence in the perception of Chinese lexical tones. The existence of this intelligence suggests that the humans can automatically extract abstract auditory rules in speech at a preattentive stage to ensure speech communication in complex and noisy auditory environments without drawing on conscious resources.

Enhancing Leadership Orientation Through Simulation

Many novice managers feel unprepared to handle some of the situations that occur as a daily part of their job. It is important to provide an environment through which novice managers can receive training and develop skills in effective communication in complex nursing environments. Simulation-based training can provide a safe, interactive way for new managers to develop their communication and leadership skills. This type of training allows novice managers to increase their confidence and improve their job satisfaction and their management skills.

Heat Maps for Intramolecular Communication in an RNP Enzyme Encoding Glutamine

Allosteric signaling within large ribonucleoproteins modulates both catalytic function and biological specificity, but the spatial extent and quantitative magnitudes of long-distance free-energy couplings have yet to be well characterized. Here, we employ pre-steady-state kinetics to generate a comprehensive mapping of intramolecular communication in the glutaminyl-tRNA synthetase:tRNA(Gln) complex. Alanine substitution at 29 positions across the protein-RNA interface reveals distinct coupling amplitudes for glutamine binding and aminoacyl-tRNA formation on the enzyme, respectively, implying the existence of multiple signaling pathways. Structural models suggest that long-range signal propagation from the tRNA anticodon is dynamically driven, whereas shorter pathways are mediated by induced-fit rearrangements. Seven protein contacts with the distal tRNA vertical arm each weaken glutamine binding affinity across distances up to 40 Å, demonstrating that negative allosteric coupling plays a key role in enforcing the selective RNA-amino acid pairing at the heart of the genetic code.