Unidirectional Transfer Research Articles

Sequencing Red Fox Y Chromosome Fragments to Develop Phylogenetically Informative SNP Markers and Glimpse Male-Specific Trans-Pacific Phylogeography.

The red fox (Vulpes vulpes) has a wide global distribution with many ecotypes and has been bred in captivity for various traits, making it a useful evolutionary model system. The Y chromosome represents one of the most informative markers of phylogeography, yet it has not been well-studied in the red fox due to a lack of the necessary genomic resources. We used a target capture approach to sequence a portion of the red fox Y chromosome in a geographically diverse red fox sample, along with other canid species, to develop single nucleotide polymorphism (SNP) markers, 13 of which we validated for use in subsequent studies. Phylogenetic analyses of the Y chromosome sequences, including calibration to outgroups, confirmed previous estimates of the timing of two intercontinental exchanges of red foxes, the initial colonization of North America from Eurasia approximately half a million years ago and a subsequent continental exchange before the last Pleistocene glaciation (~100,000 years ago). However, in contrast to mtDNA, which showed unidirectional transfer from Eurasia to North America prior to the last glaciation, the Y chromosome appears to have been transferred from North America to Eurasia during this period. Additional sampling is needed to confirm this pattern and to further clarify red fox Y chromosome phylogeography.

Plasmon-enhanced unidirectional charge transfer for efficient solar water oxidation.

Precise modulation and nano-engineering of photoelectrochemical (PEC) materials, with high-speed charge separation efficiency and broad spectral response, are of significant importance in improving the PEC catalytic activities. Herein, by rational design of material structures, 3D-coaxial plasmonic hetero-nanostructures (carbon cloth@TiO2@SrTiO3-Au, CC@TiO2@SrTiO3-Au) are tactfully fabricated, which exhibit superior solar energy conversion efficiency in PEC water splitting with a current density reaching up to 23.56 mA cm-2 (1.23 V vs. RHE). More specific research and in-depth simulations reveal that the enhanced PEC performance should be attributed to the high-speed charge transfer channels of CC@TiO2@SrTiO3 and excellent light utilization ability stemming from the surface plasmon resonance and strong light-scattering of the 3D-coaxial frameworks. This study provides new strategies for the design of plasmon-enhanced PEC nanocatalysts and will benefit the development of photoelectric energy conversion.

Asymmetric Network Effects in the Integration of Digital Platforms

We have witnessed an increasing number of mergers and acquisitions (M&A) between two-sided digital platforms, generally involving a unidirectional resource transfer policy from the acquired to the acquiring platform. This scenario may incur an asymmetric network effect that has not been explored in the extant literature. Using a unique dataset from Dianping and Meituan, two digital platforms similar to Yelp, we explore whether and how the unidirectional data integration policy causes a positive network effect, as reflected by the increments of user engagement on each side of the M&A. We measure user engagement in two dimensions, namely, quantity measures (e.g., number of total reviews) and quality measures (e.g., number of reviews with pictures and length of review). The results show that the policy enhances both measures of user engagement for the acquired and acquiring platforms but that its effects on user engagement on the acquiring platform are larger than those on the acquired platform. We propose three mechanisms: the network size effect, self-image management effect, and social learning effect to explain the possible impacts of platform integration on user engagement, and we conduct single-group interrupted time-series analyses to test the effects. We further conduct three sets of supplementary analyses. We find that, first, the policy not only expands its user base but also boosts the contribution enthusiasm of current users. Second, we clarify how the benefits of platform integration are shaped by merchant features such as per capita consumption and whether a merchant has chain stores. Third, we focus on the multi-homing phenomenon of merchants and find that multi-homing merchants benefit more from platform integration. The findings of this study deepen our understanding of the connections between unidirectional resource transfer and the asymmetric network effect in the context of the integration of two digital platforms.

Fabrication of janus type bi-layer polymeric membranes for advance water purification

Membrane technology plays a vital role in various applications like desalination, ultrafiltration, nano-filtration, reverse osmosis and wastewater treatment. Janus membranes (JMs) are a unique class of polymers having divergent hydrophilic/hydrophobic properties on both sides of their interface. JMs have been exclusively used in the fields of fluid flow to induce unidirectional fluid transportation at the required interfaces. Herein, we report the fabrication of two Janus type bi-layer polymeric membranes with hydrophilic and hydrophobic surfaces on opposite sides using a simple doctor blading method. First bi-layer Janus membrane consists of polyvinylidene fluoride (PVDF) coating on cellulose cotton fabric (CPV). Second bi-layer Janus membrane (NPV) consists of partly hydrophilic nylon 6, 10 top layer and hydrophobic PVDF bottom layer. PVDF and nylon 6, 10 solutions are cast of a suitable thickness over the respective bottom layers. Prepared Janus membranes were characterised by SEM, FTIR and UV–Visible spectroscopy. Water contact angle measurements confirmed the hydrophilic and hydrophobic behaviour on opposite sides of the membranes. Porosity and equilibrium water content measurements established that both Janus membranes retain native properties of their constituent polymers. These newly engineered Janus type polymeric membranes could find potential application in creating unidirectional fluid flow transfer such as oil–water separations.

Exploring Half-Duplex Communication of NFC Read/Write Mode for Secure Multi-Factor Authentication

Near Field Communication (NFC) is a prominent short-range, contact-less communication technology, which is rapidly getting popular in modern smart devices. For communication between two active devices via NFC, applications generally choose the peer-to-peer operation mode. In this paper, we exploit the possibility of using the NFC read/write mode, designed primarily for unidirectional data transfer from an active NFC reader to a passive NFC tag, for bi-directional half-duplex communication between two active NFC devices. The advantages of using the NFC read/write mode include low protocol overhead and permitting different data formats. However, the challenges are avoiding the reader collision problem, maintaining a secure session, and completing all transactions in an acceptable time frame. In this paper, we address the above challenges and propose a methodology for efficient communication between active NFC devices using NFC read/write mode. To evaluate the scheme, we design a secure Multi-Factor Authentication (MFA) system that requires bi-directional communication for mutually authenticating two NFC devices. The proposed methodology is experimentally verified using NFC-enabled Android smartphones and a Kerberos server as the third-party authenticator.

ФОРМИРОВАНИЕ СОЦИАЛЬНОЙ КОМПЕТЕНЦИИ КАК ФАКТОР ПОЛНОЦЕННОГО РАЗВИТИЯ ЛИЧНОСТНЫХ КАЧЕСТВ БУДУЩИХ СОТРУДНИКОВ УГОЛОВНО-ИСПОЛНИТЕЛЬНОЙ СИСТЕМЫ

The article examines the process and features of social competence development of departmental universities` cadets as future penal officers. The concept of “competence-based model of personnel training” is characterized. In modern social and cultural conditions, the effectiveness of the upbringing process is associated with the creation of a developing educational environment in society as a system of conditions and opportunities for personal self-development. The organization of upbringing as a pedagogical process in a university is considered as effective not only within the framework of traditional pedagogy, based on the principles of which the process of upbringing departmental universities` cadets is a unidirectional transfer of previous samples of cultural and historical experience and the reproduction of its already "ready" values, cultural forms, norms and rules of social interaction and communication. The main educational goals of higher education in modern social and economic conditions are analyzed, which consist in the formation of social and professional competence in graduates, in the upbringing of the cadet` personality of a departmental university with the qualities of civic responsibility and patriotism, actively participating in the economic and social, cultural life of the country.

Towards decolonising research methods training: the development of a locally responsive online learning course on research methods for mental health in war and conflict for researchers and practitioners in the Gaza Strip.

Concerns exist that online learning directed at non-Western settings to strengthen research capacity imposes Western-centric epistemology, provides unidirectional transfer of knowledge, and neglects local paradigms and expertise. We argue that a plurality of voices, histories and epistemologies are essential to strengthen research capacity. We share our experience developing and teaching an online course for mental health professionals and researchers in the Gaza Strip. Birzeit University and King's College London developed and delivered the course equally, focusing on the intersection between qualitative research methods, mental health and conflict, and addressing local research needs. We incorporated local case studies and expertise, encouraged interaction in English and Arabic, and stimulated critique of Western theories. Seventeen participated, 12 completed the pre-course questionnaire, 15 completed the post-course questionnaire and four undertook semi-structured interviews. Our pre-course survey showed participants most needed coding and qualitative data analysis skills. Post-course findings showed improved qualitative research skills. Most agreed the course was comprehensive and well delivered, with relevant case studies. Three themes were identified: (1) the course was locally contextualised and met students' needs; (2) the course fostered dialogic and multi-directional learning and (3) suggestions for improvements. Several participants wanted some topics in greater depth and further specialised training. A few suggested the course be in Arabic. Fostering multi-directional learning is key for non-Western knowledge, epistemologies, and languages to gain prominence in Western academia. A social transformation would see local researchers and educators engage with and use local methods and paradigms in mental health in war and conflict.

Buck–Boost Three-Level Semi-Dual-Bridge Resonant Isolated DC–DC Converter

The semi-dual-bridge resonant isolated dc–dc converter (SDBRC), as a class of emerging topologies, is suitable for the application situation that requires only the unidirectional power transfer while a wide buck–boost voltage conversion range. In this article, a three-level SDBRC is proposed. Its operation principle is analyzed, and the transfer power and voltage conversion ratio as the functions of the two phase shifts are derived. Furthermore, a coordinated control rule of the two phase shifts is proposed, which ensures the monotonicity between the phase shifts and the average output power over the entire power/voltage range. The voltage stress of the power devices of the proposed topology is reduced to half of the power supply voltage; therefore, the cost and ON-state loss of the power switches are effectively reduced. The detailed simulation and experimental results validate the correctness and feasibility of the proposed topology and its modulation strategy.

The influence of different ZnO nanostructures on NO2 sensing performance

Three different ZnO nanostructures (nanorods/flowers/spheres) were prepared through facile hydrothermal method or water bath, whose sensing properties to NO2 were investigated in detail at room temperature activated by UV light (365 nm LED). The sensing results showed that ZnO nanospheres exhibit the highest response of 29.4–5 ppm NO2, which can be attributed to their biggest specific surface area and the most amount of adsorbed oxygen species on the surface. In contrast, ZnO nanorods show the fastest response and recovery speed (9 and 18 s to 5 ppm NO2, respectively) due to their highest crystallinity, least surface defects and unidirectional electron transfer path, which is much faster than most reported literatures. With regard to the ZnO nanoflowers, both the gas-sensing response and the response and recovery speed are between ZnO nanorods and ZnO nanospheres. Furthermore, the stability, selectivity, and the moisture resistance of three different ZnO nanostructures were also researched.

Unidirectional two-way optical frequency comparison and its fundamental limitations.

High-quality frequency transfer based on existing telecommunication fiber links allows state-of-the-art microwave and optical clocks to be compared on a continental and potentially even intercontinental scale. We present a half-a-year-long data set of unidirectional optical frequency transfer over a 2×43km urban fiber link. We observe a relative frequency instability of 8.0×10-16 at 1 s and at best 6.0×10-18 at 106s integration time. Our results show that the unidirectional two-way method gives the possibility to perform comparisons of international primary standards over fiber links faster than over satellite links. Moreover, we investigate the major limiting factors of such a unidirectional setup.

HACANCOi: a new H\u03b1-detected experiment for backbone resonance assignment of intrinsically disordered proteins

Unidirectional coherence transfer is highly efficient in intrinsically disordered proteins (IDPs). Their elevated ps-ns timescale dynamics ensures long transverse (T2) relaxation times allowing sophisticated coherence transfer pathway selection in comparison to folded proteins. 1Hα-detection ensures non-susceptibility to chemical exchange with the solvent and enables chemical shift assignment of consecutive proline residues, typically abundant in IDPs. However, many IDPs undergo a disorder-to-order transition upon interaction with their target protein, which leads to the loss of the favorable relaxation properties. Long coherence transfer routes now result in prohibitively large decrease in sensitivity. We introduce a novel 4D 1Hα-detected experiment HACANCOi, together with its 3D implementation, which warrant high sensitivity for the assignment of proline-rich regions in IDPs in complex with a globular protein. The experiment correlates 1Hαi, 13Cαi, 15Ni and ^{13} C^{prime}_{i} spins by transferring the magnetization concomitantly from 13Cαi to 15Ni and ^{13} C^{prime}_{i}. The B1 domain of protein G (GB1), and the enteropathogenic E.coli EspF in complex with human SNX9 SH3, serve as model systems to demonstrate the attainable sensitivity and successful sequential assignment.

Mimicking Natural Photosynthesis: Designing Ultrafast Photosensitized Electron Transfer into Multiheme Cytochrome Protein Nanowires.

Efficient nanomaterials for artificial photosynthesis require fast and robust unidirectional electron transfer (ET) from photosensitizers through charge-separation and accumulation units to redox-active catalytic sites. We explored the ultrafast time-scale limits of photo-induced charge transfer between a Ru(II)tris(bipyridine) derivative photosensitizer and PpcA, a 3-heme c-type cytochrome serving as a nanoscale biological wire. Four covalent attachment sites (K28C, K29C, K52C, and G53C) were engineered in PpcA enabling site-specific covalent labeling with expected donor-acceptor (DA) distances of 4–8 Å. X-ray scattering results demonstrated that mutations and chemical labeling did not disrupt the structure of the proteins. Time-resolved spectroscopy revealed three orders of magnitude difference in charge transfer rates for the systems with otherwise similar DA distances and the same number of covalent bonds separating donors and acceptors. All-atom molecular dynamics simulations provided additional insight into the structure-function requirements for ultrafast charge transfer and the requirement of van der Waals contact between aromatic atoms of photosensitizers and hemes in order to observe sub-nanosecond ET. This work demonstrates opportunities to utilize multi-heme c-cytochromes as frameworks for designing ultrafast light-driven ET into charge-accumulating biohybrid model systems, and ultimately for mimicking the photosynthetic paradigm of efficiently coupling ultrafast, light-driven electron transfer chemistry to multi-step catalysis within small, experimentally versatile photosynthetic biohybrid assemblies.

Transfer Entropy Analysis of Interactions between Bats Using Position and Echolocation Data.

Many animal species, including many species of bats, exhibit collective behavior where groups of individuals coordinate their motion. Bats are unique among these animals in that they use the active sensing mechanism of echolocation as their primary means of navigation. Due to their use of echolocation in large groups, bats run the risk of signal interference from sonar jamming. However, several species of bats have developed strategies to prevent interference, which may lead to different behavior when flying with conspecifics than when flying alone. This study seeks to explore the role of this acoustic sensing on the behavior of bat pairs flying together. Field data from a maternity colony of gray bats (Myotis grisescens) were collected using an array of cameras and microphones. These data were analyzed using the information theoretic measure of transfer entropy in order to quantify the interaction between pairs of bats and to determine the effect echolocation calls have on this interaction. This study expands on previous work that only computed information theoretic measures on the 3D position of bats without echolocation calls or that looked at the echolocation calls without using information theoretic analyses. Results show that there is evidence of information transfer between bats flying in pairs when time series for the speed of the bats and their turning behavior are used in the analysis. Unidirectional information transfer was found in some subsets of the data which could be evidence of a leader–follower interaction.

On-chip broadband nonreciprocal light storage

AbstractBreaking the symmetry between forward- and backward-propagating optical modes is of fundamental scientific interest and enables crucial functionalities, such as isolators, circulators, and duplex communication systems. Although there has been progress in achieving optical isolation on-chip, integrated broadband nonreciprocal signal processing functionalities that enable transmitting and receiving via the same low-loss planar waveguide, without altering the frequency or mode of the signal, remain elusive. Here, we demonstrate a nonreciprocal delay scheme based on the unidirectional transfer of optical data pulses to acoustic waves in a chip-based integration platform. We experimentally demonstrate that this scheme is not impacted by simultaneously counterpropagating optical signals. Furthermore, we achieve a bandwidth more than an order of magnitude broader than the intrinsic optoacoustic linewidth, linear operation for a wide range of signal powers, and importantly, show that this scheme is wavelength preserving and avoids complicated multimode structures.

Maternal high fat diet-induced obesity affects trophoblast differentiation and placental function in mice†.

Evidence suggests that maternal obesity (MO) can aggravate placental function causing severe pathologies during the perinatal window. However, molecular changes and mechanisms of placental dysfunction remain largely unknown. This work aimed to decipher structural and molecular alterations of the placental transfer zone associated with MO. To this end, mice were fed a high fat diet (HFD) to induce obesity before mating, and pregnant dams were sacrificed at E15.5 to receive placentas for molecular, histological, and ultrastructural analysis and to assess unidirectional materno-fetal transfer capacity. Laser-capture microdissection was used to collect specifically placental cells of the labyrinth zone for proteomics profiling. Using BeWo cells, fatty acid-mediated mechanisms of adherens junction stability, cell layer permeability, and lipid accumulation were deciphered. Proteomics profiling revealed downregulation of cell adhesion markers in the labyrinth zone of obese dams, and disturbed syncytial fusion and detachment of the basement membrane (BM) within this zone was observed, next to an increase in materno-fetal transfer in vivo across the placenta. We found that fetuses of obese dams develop a growth restriction and in those placentas, labyrinth zone volume-fraction was significantly reduced. Linoleic acid was shown to mediate beta-catenin level and increase cell layer permeability in vitro. Thus, MO causes fetal growth restriction, molecular and structural changes in the transfer zone leading to impaired trophoblast differentiation, BM disruption, and placental dysfunction despite increased materno-fetal transfer capacity. These adverse effects are probably mediated by fatty acids found in HFD demonstrating the need for obesity treatment to mitigate placental dysfunction and prevent offspring pathologies.

Influence of electric field on nanoconfined proton behaviours: A molecular dynamics simulation

We report a molecular dynamics study of the effect of a static electric field on the structural and dynamical properties of confined protons and water in a fluorinated nanochannel. The applied electric field generates a counter electric field inside the channel, which inhibits unidirectional proton transfer inside the nanochannel. As the external electric field is intensified to some extent, protons have the ability to overcome the internal electric field and effectively complete the transfer through the channel. Further intensifying the electric field produces an additional pathway for proton diffusion and enhances the contribution of the vehicle mechanism to proton transfer in the channel. Nevertheless, the electric field has little effect on the spiral-like hydrogen bond network confined in the channel and maintains a confined hydrogen bond network suitable for proton hopping. These findings deepen the understanding of the effect of electric field on proton transfer along a proton-conductive channel.

Conservation of Cell Communication Systems in Invertebrate Host-Defence Mechanisms: Possible Role in Immunity and Disease.

Innate immunity is continuously revealing multiple and highly conserved host–defence mechanisms. Studies on mammalian immunocytes are showing different communication systems that may play a role in coordinating innate immune responses also in invertebrates. Extracellular traps (ETs) are an immune response by which cells release net-like material, including DNA, histones and proteins. ETs are thought to immobilise and kill microorganisms, but are also involved in inflammation and autoimmune disease. Immune cells are also known to communicate through extracellular vesicles secreted in the extracellular environment or exosomes, which can carry a variety of different signalling molecules. Tunnelling nanotubes (TNTs) represent a direct cell-to-cell communication over a long distance, that allow for bi- or uni-directional transfer of cellular components between cells. Their functional role in a number of physio-pathological processes, including immune responses and pathogen transfer, has been underlined. Although ETs, exosomes, and TNTs have been described in invertebrate species, their possible role in immune responses is not fully understood. In this work, available data on these communication systems are summarised, in an attempt to provide basic information for further studies on their relevance in invertebrate immunity and disease.

Pathways to educational change revisited– controversies and advances in the German teacher education system

This article contributes to the discourse of innovation and transfer strategies in German teacher education by (1) providing a conceptual analysis of prevalent approaches and (2) introducing a transdisciplinary perspective. The conceptual analysis indicates that top-down and bottom-up approaches lack either transformative momentum or scientific rigor. Collaborative approaches aim to mitigate this dilemma, but remain biased towards unidirectional innovation and transfer processes. In contrast, transdisciplinary approaches advocate for integrative and systemic pathways for educational change, which interlinks research and practice in teaching and teacher education. Illustrating examples from a boundary-crossing research and development project support this perspective.

Influence of polypropylene and steel fibres on thermal spalling and physical-mechanical properties of concrete under different heating rates

This study investigates three concrete compositions: a control concrete, a reinforced concrete containing 60 kg/m3 of steel fibres, and a hybrid concrete containing 60 kg/m3 of steel fibres and 0.75 kg/m3 of polypropylene fibres. Cylindrical specimens were manufactured and subjected to two heating rates (10 °C/min and the ISO 834 fire standard) to study their spalling sensitivity. Moreover, unidirectional heat transfer and pressure measurements were performed on slabs heated at 10 °C/min to 600 °C. To understand the influence of fibres on spalling processes more clearly, the thermal properties were studied during heating and cooling: the gas permeability, compressive strength, and Young’s modulus of specimens were measured after a heating and cooling cycle at 0.5 °C/min. The results show that the spalling phenomenon was more severe for cylindrical specimens than for slabs. The addition of 60 kg/m3 of steel fibres had an unfavourable influence on spalling, especially during the ISO 834 fire test. The addition of 0.75 kg/m3 of polypropylene fibres allowed the concretes containing steel fibres to avoid spalling, regardless of the thermal loading conditions.

Collecting up to 115% of Singlet-Fission Products by Single-Walled Carbon Nanotubes.

In this contribution, we focused on integrating a phenylene-bridged dibenzodiazahexacene dimer (o-DAD), which is singlet fission (SF) active, onto single-walled carbon nanotubes (SWCNTs) as a low-energy sink for energetically low lying excited states that stem from SF. Spectroscopic and microscopic assays assisted in documenting that SWCNT/o-DAD feature high stability in THF as a result of electronic interactions between the individual constituents. For example, statistical Raman analysis underlined n-doping of SWCNTs in the presence of o-DAD. Fluorescence spectroscopy prompted an energy transfer between the individual constituents, a conclusion that was exclusively derived from the quenching of the o-DAD-centered fluorescence. Excitation spectroscopy with a focus on the SWCNT fluorescence confirmed independently this conclusion by showing o-DAD-centered features. Our work was rounded off by time-resolved transient absorption measurements with SWCNT/o-DAD, in which evidence was gathered for the sequential o-DAD-centered SF with an efficiency of 112% followed by a unidirectional energy transfer from o-DAD to SWCNT and a rapid deactivation. The energy transfer efficiency from SF products such as (S1S0)CT and 1(T1T1) exceeded the 100% threshold with values of 115%, which is conventionally found in energy transfer schemes.