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  • 3D -printed high-NA catadioptric thin lens for suppression of XPM background in Stimulated Raman Scattering microscopy

    Bertoncini, Andrea; Laptenok, Siarhei; Genchi, Luca; Rajamanickam, Vijayakumar Palanisamy; Liberale, Carlo (Journal of Biophotonics, Wiley, 2020-07-13) [Article]
    Stimulated Raman Scattering (SRS) is a fast chemical imaging technique with remarkable bio-science applications. Cross Phase Modulation (XPM) is a ubiquitous non-linear phenomenon that can create spurious background signals that render difficult a high-contrast imaging in SRS measurements. The XPM-induced signal is usually suppressed using high Numerical Aperture (NA) microscope objectives or condensers to collect the transmitted excitation beam. However, these high-NA optics feature short working distances, hence they are not compatible with stage-top incubators, that are necessary to perform live-cell time-lapse experiments in controlled environments. Here,we showa 3D printed high-NAcompact catadioptric lens that fits inside stage-top incubators and allows the collection of XPM-free SRS signals. The lens delivers SRS images and spectra with a quality comparable to a signal collection with a high-NA microscope objective. We also demonstrate the compatibility of the 3D printed lens with other non-linear microscopies usually associated with SRS in multimodal microscopes.
  • Translational Molecular Ecology in practice: Linking DNA-based methods to actionable marine environmental management

    Aylagas, Eva; Aylagas, Eva; Pochon, Xavier; Zaiko, Anastasija; Keeley, Nigel; Bruce, Kat; Hong, Pei-Ying; Ruiz, Gregory M.; Stein, Eric D.; Theroux, Susanna; Geraldi, Nathan; Ortega, Alejandra; Gajdzik, Laura; Coker, Darren James; Katan, Yasser; Hikmawan, Tyas; Saleem, Ammar; Alamer, Sultan; Jones, Burton; Duarte, Carlos M.; Pearman, John; Carvalho, Susana (Science of The Total Environment, Elsevier BV, 2020-07-12) [Article]
    Molecular-based approaches can provide timely biodiversity assessments, showing an immense potential to facilitate decision-making in marine environmental management. However, the uptake of molecular data into environmental policy remains minimal. Here, we showcase a selection of local to global scale studies applying molecular-based methodologies for environmental management at various stages of implementation. Drawing upon lessons learned from these case-studies, we provide a roadmap to facilitate applications of DNA-based methods to marine policies and to overcome the existing challenges. The main impediment identified is the need for standardized protocols to guarantee data comparison across spatial and temporal scales. Adoption of Translational Molecular Ecology – the sustained collaboration between molecular ecologists and stakeholders, will enhance consensus with regards to the objectives, methods, and outcomes of environmental management projects. Establishing a sustained dialogue among stakeholders is the key to accelerating the adoption of molecular-based approaches for marine monitoring and assessment.
  • Synthesis of Copper and Copper Oxide Nanomaterials by Pulsed Electric Field in Water with Various Electrical Conductivities

    Hamdan, Ahmad; Glad, Xavier; Cha, Min Suk (Nanomaterials, MDPI AG, 2020-07-10) [Article]
    <jats:p>Nanomaterial synthesis is a hot research subject that has been extensively studied in the last two decades. Recently, plasmas in liquid systems have been proposed as an efficient means of synthesizing various types of nanomaterials. The formation processes implicate many physical and chemical phenomena that take place at the electrode surface, as well as in the plasma volume, which renders it difficult to fully understand the underlying mechanisms. In this study, we assess the effect of electric field on nanomaterial synthesis in a system composed of two copper electrodes immersed in water, in the absence of an electrical discharge. The obtained results indicate that various nanostructures, including copper nanoparticles, copper oxide nanowires, and/or hollow nanoparticles, may be produced, depending on the electrical conductivity of the solution (adjusted by adding highly diluted HCl to deionized water). The materials synthesized herein are collected and characterized, and a formation mechanism is proposed. Overall, our results provide insight into the physical and chemical phenomena underlying nanomaterial synthesis in plasmas in liquid.</jats:p>
  • BAlN alloy for enhanced two-dimensional electron gas characteristics of GaN/AlGaN heterostructures

    Lin, Rongyu; Liu, Xinwei; Liu, Kaikai; Lu, Yi; Liu, Xinke; Li, Xiaohang (Journal of Physics D: Applied Physics, IOP Publishing, 2020-07-10) [Article]
    The emerging wide bandgap BAlN alloys have potentials for improved III-nitride power devices including high electron mobility transistor (HEMT). Yet few relevant studies have been carried. In this work, we have investigated the use of the B0.14Al0.86N alloy as part or entirety of the interlayer between the GaN buffer and the AlGaN barrier in the conventional GaN/AlGaN heterostructure. The numerical results show considerable improvement of the two-dimensional electron gas (2DEG) concentration with small 2DEG leakage into the ternary layer by replacing the conventional AlN interlayer by either the B0.14Al0.86N interlayer or the B0.14Al0.86N/AlN hybrid interlayer. Consequently, the transfer characteristics can be improved. The saturation current can be enhanced as well. For instance, the saturation currents for HEMTs with the 0.5 nm B0.14Al0.86N/0.5 nm AlN hybrid interlayer and the 1 nm B0.14Al0.86N interlayer are 5.8% and 2.2% higher than that for the AlN interlayer when VGS-Vth= +3 V.
  • Defect Passivation in Perovskite Solar Cells by Cyano-Based π-Conjugated Molecules for Improved Performance and Stability

    Wang, Kai; Liu, Jiang; Yin, Jun; Aydin, Erkan; Harrison, George T.; Liu, Wenzhu; Chen, Shanyong; Mohammed, Omar F.; De Wolf, Stefaan (Advanced Functional Materials, Wiley, 2020-07-09) [Article]
    Defects at the surface and grain boundaries of metal–halide perovskite films lead to performance losses of perovskite solar cells (PSCs). Here, organic cyano-based π-conjugated molecules composed of indacenodithieno[3,2-b]thiophene (IDTT) are reported and it is found that their cyano group can effectively passivate such defects. To achieve a homogeneous distribution, these molecules are dissolved in the antisolvent, used to initiate the perovskite crystallization. It is found that these molecules are self-anchored at the grain boundaries due to their strong binding to undercoordinated Pb2+. On a device level, this passivation scheme enhances the charge separation and transport at the grain boundaries due to the well-matched energetic levels between the passivant and the perovskite. Consequently, these benefits contribute directly to the achievement of power conversion efficiencies as high as 21.2%, as well as the improved environmental and thermal stability of the PSCs. The surface treatment provides a new strategy to simultaneously passivate defects and enhance charge extraction/transport at the device interface by manipulating the anchoring groups of the molecules.
  • Simplified detection of polyhistidine-tagged proteins in gels and membranes using a UV-excitable dye and a multiple chelator head pair

    Raducanu, Vlad-Stefan; Isaioglou, Ioannis; Raducanu, Daniela-Violeta; Merzaban, Jasmeen; Hamdan, Samir (Journal of Biological Chemistry, American Society for Biochemistry & Molecular Biology (ASBMB), 2020-07-09) [Article]
    <jats:p>The polyhistidine tag (His-tag) is one of the most popular protein tags used in the life sciences. Traditionally, the detection of His-tagged proteins relies on immunoblotting with anti-His antibodies. This approach is laborious for certain applications such as protein purification, where time and simplicity are critical. The His-tag can also be directly detected by metal ion–loaded N-nitrilotriacetic acid–based chelator heads conjugated to fluorophores, which is a convenient alternative method to immunoblotting. Typically, such chelator heads are conjugated to either green or red fluorophores, the detection of which requires specialized excitation sources and detection systems. Here, we demonstrate that post-run staining is ideal for His-tag detection by metal ion–loaded and fluorescently labeled chelator heads in PAGE and blot membranes. Additionally, by comparing the performances of different chelator heads, we show how differences in microscopic affinity constants translate to macroscopic differences in the detection limits in environments with limited diffusion, such as PAGE. On the basis of these results, we devise a simple approach, called UVHis-PAGE, that uses metal ion–loaded and fluorescently labeled chelator heads to detect His-tagged proteins in PAGE and blot membranes. Our method uses a UV transilluminator as an excitation source, and the results can be visually inspected by the naked eye.</jats:p>
  • NIR multiphoton ablation of cancer cells, fluorescence quenching and cellular uptake of dansyl-glutathione-coated gold nanoparticles

    Buonerba, Antonio; Lapenta, Rosita; Donniacuo, Anna; Licasale, Magda; Vezzoli, Elena; Milione, Stefano; Capacchione, Carmine; Tecce, Mario Felice; Falqui, Andrea; Piacentini, Roberto; Grassi, Claudio; Grassi, Alfonso (Scientific Reports, Springer Science and Business Media LLC, 2020-07-09) [Article]
    Theranostics based on two-photon excitation of therapeutics in the NIR region is an emerging and powerful tool in cancer therapy since this radiation deeply penetrates healthy biological tissues and produces selective cell death. Aggregates of gold nanoparticles coated with glutathione corona functionalized with the dansyl chromophore (a-DG-AuNPs) were synthesized and found efficient nanodevice for applications in photothermal therapy (PTT). Actually the nanoparticle aggregation enhances the quenching of radiative excitation and the consequent conversion into heat. The a-DG-AuNPs are readily internalized in Hep G2 where the chromophore acts as both antenna and transducer of the NIR radiation under two-photons excitation, determining efficient cell ablation via photothermal effect.
  • Topology Meets Reticular Chemistry for Chemical Separations: MOFs as a Case Study

    Bhatt, Prashant; Guillerm, Vincent; Datta, Shuvo Jit; Shkurenko, Aleksander; Eddaoudi, Mohamed (Chem, Elsevier BV, 2020-07-09) [Article]
    Chemical separations are of prime industrial importance; however, they consume a large portion of total industrial energy. Credibly, adsorbent-based separation methods offer the prospective to drastically lessen the energy demand of conventional energy-intensive separation processes. Prominently, a special class of porous materials, namely metal-organic frameworks (MOFs), are reasonably positioned to address various demanding separations in an energy-efficient manner. Out of a myriad of possible topologies for the construction of MOFs, face-transitive nets affording a sole type of window, preferably defined by three- or four-membered rings, can be regarded as ideal blueprints for the construction of MOFs for targeted separations. Intricate separations by MOFs based on some of these topologies are discussed, highlighting the effect of appropriate pore aperture and channel size with prerequisite functional groups on their separation performance. MOFs based on face-transitive nets offer great potential as effective fillers for the construction of practical mixed-matrix membranes (MMMs) with improved separation properties over conventional polymeric membranes.
  • Physical and economical evaluation of laboratory-scale membrane bioreactor by long-term relative cost–benefit analysis

    Ayub, Mariam; Saeed, Nadeeha; Chung, Shinho; Nawaz, Muhammad Saqib; Ghaffour, NorEddine (Journal of Water Reuse and Desalination, IWA Publishing, 2020-07-08) [Article]
    Two laboratory-scale single-stage submerged membrane bioreactors (MBRs) were operated in parallel to examine the effect of different flux conditions and several fouling mitigation methods. After control operation (filtration only), three fouling control methods (relaxation, standard backwash and chemical backwash) at 27 LMH flux and four different flux conditions (54, 36, 27 and 18 LMH) with standard backwash were applied. Physical performance of MBRs was evaluated based on the operational duration to reach maximum transmembrane pressure and the volume of permeate produced during the operational duration. Then relative cost–benefit analysis was carried out. Results showed that the combination of chemical backwash and standard backwash was the most effective for fouling mitigation in terms of physical improvement of MBR performance. However, the combination proved less economical (400% + α relative cost) than standard backwash alone (343% relative cost), because of the additional cost for pumps and chemical. It also showed that lower flux (18 LMH) is desirable as it showed better physical performance (1,770% improvement as compared to the highest flux, 54 LMH) and proved more economical than higher flux configuration. Therefore, it is concluded that the operation with standard backwash at the lowest possible flux is the best combination to improve MBR performance as well as long-term cost–benefit.
  • Natal philopatry increases relatedness within groups of coral reef cardinalfish

    Rueger, Theresa; Harrison, Hugo B.; Buston, Peter M.; Gardiner, Naomi M.; Berumen, Michael L.; Jones, G. P. (Proceedings of the Royal Society B: Biological Sciences, The Royal Society, 2020-07-08) [Article]
    A central issue in evolutionary ecology is how patterns of dispersal influence patterns of relatedness in populations. In terrestrial organisms, limited dispersal of offspring leads to groups of related individuals. By contrast, for most marine organisms, larval dispersal in open waters is thought to minimize kin associations within populations. However, recent molecular evidence and theoretical approaches have shown that limited dispersal, sibling cohesion and/or differential reproductive success can lead to kin association and elevated relatedness. Here, we tested the hypothesis that limited dispersal explains small-scale patterns of relatedness in the pajama cardinalfish Sphaeramia nematoptera. We used 19 microsatellite markers to assess parentage of 233 juveniles and pairwise relatedness among 527 individuals from 41 groups in Kimbe Bay, Papua New Guinea. Our findings support three predictions of the limited dispersal hypothesis: (i) elevated relatedness within groups, compared with among groups and elevated relatedness within reefs compared with among reefs; (ii) a weak negative correlation of relatedness with distance; (iii) more juveniles than would be expected by chance in the same group and the same reef as their parents. We provide the first example for natal philopatry at the group level causing small-scale patterns of genetic relatedness in a marine fish.
  • Chemoselective Hydrogenation of Alkynes to (Z)-Alkenes Using an Air-Stable Base Metal Catalyst

    Zubar, Viktoriia; Sklyaruk, Jan; Brzozowska, Aleksandra; Rueping, Magnus (Organic Letters, American Chemical Society (ACS), 2020-07-08) [Article]
    A highly selective hydrogenation of alkynes using an air-stable and readily available manganese catalyst has been achieved. The reaction proceeds under mild reaction conditions and tolerates various functional groups, resulting in (Z)-alkenes and allylic alcohols in high yields. Mechanistic experiments suggest that the reaction proceeds via a bifunctional activation involving metal–ligand cooperativity.
  • Draft Genome Sequences of Three Bacillus Species Isolated from Biofouled Reverse-Osmosis Membranes

    Rehman, Zahid Ur; Iftikhar, Muhammad Ali; Leiknes, TorOve (Microbiology Resource Announcements, American Society for Microbiology, 2020-07-08) [Article]
    <jats:title>ABSTRACT</jats:title> <jats:p>Here, we present the draft genome sequences of three bacteria belonging to the genus <jats:italic>Bacillus</jats:italic> which were isolated from biofouled reverse-osmosis (RO) membranes harvested from a full-scale desalination plant. The sizes of the assembled genomes for RO1, RO2, and RO3 were 4.22 Mb, 4.15 Mb, and 4.23 Mb, respectively.</jats:p>
  • Seagrass losses since mid-20th century fuelled CO 2 emissions from soil carbon stocks

    Salinas, Cristian; Duarte, Carlos M.; Lavery, P. S.; Masqué, Pere; Arias-Ortiz, Ariane; Leon, Javier X.; Callaghan, David; Kendrick, G. A.; Serrano, Oscar (Global Change Biology, Wiley, 2020-07-07) [Article]
    Seagrass meadows store globally significant organic carbon (Corg) stocks which, if disturbed, can lead to CO2 emissions, contributing to climate change. Eutrophication and thermal stress continue to be a major cause of seagrass decline worldwide, but the associated CO2 emissions remain poorly understood. This study presents comprehensive estimates of seagrass soil Corg erosion following eutrophication-driven seagrass loss in Cockburn Sound (23 km2 between 1960s and 1990s) and identifies the main drivers. We estimate that shallow seagrass meadows (<5 m depth) had significantly higher Corg stocks in 50 cm thick soils (4.5 ± 0.7 kg Corg/m2) than previously vegetated counterparts (0.5 ± 0.1 kg Corg/m2). In deeper areas (>5 m), however, soil Corg stocks in seagrass and bare but previously vegetated areas were not significantly different (2.6 ± 0.3 and 3.0 ± 0.6 kg Corg/m2, respectively). The soil Corg sequestration capacity prevailed in shallow and deep vegetated areas (55 ± 11 and 21 ± 7 g Corg m−2 year−1, respectively), but was lost in bare areas. We identified that seagrass canopy loss alone does not necessarily drive changes in soil Corg but, when combined with high hydrodynamic energy, significant erosion occurred. Our estimates point at ~0.20 m/s as the critical shear velocity threshold causing soil Corg erosion. We estimate, from field studies and satellite imagery, that soil Corg erosion (within the top 50 cm) following seagrass loss likely resulted in cumulative emissions of 0.06–0.14 Tg CO2-eq over the last 40 years in Cockburn Sound. We estimated that indirect impacts (i.e. eutrophication, thermal stress and light stress) causing the loss of ~161,150 ha of seagrasses in Australia, likely resulted in the release of 11–21 Tg CO2-eq since the 1950s, increasing cumulative CO2 emissions from land-use change in Australia by 1.1%–2.3% per annum. The patterns described serve as a baseline to estimate potential CO2 emissions following disturbance of seagrass meadows.
  • SARS-CoV-2 infections and COVID-19 mortalities strongly correlate with ACE1 I/D genotype.

    Yamamoto, Naoki; Ariumi, Yasuo; Nishida, Nao; Yamamoto, Rain; Bauer, Georg; Gojobori, Takashi; Shimotohno, Kunitada; Mizokami, Masashi (Gene, Elsevier BV, 2020-07-07) [Article]
    Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19). The relentless spread and pathogenicity of the virus have become a global public health emergency. One of the striking features of this pandemic is the pronounced impact on specific regions and ethnic groups. In particular, compared with East Asia, where the virus first emerged, SARS-CoV-2 has caused high rates of morbidity and mortality in Europe. This has not been experienced in past global viral infections, such as influenza, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) and is unique to SARS-CoV-2. For this reason, we investigated the involvement of genetic factors associated with SARS-CoV-2 infection with a focus on angiotensin-converting enzyme (ACE)-related genes, because ACE2 is a receptor for SARS-CoV-2. We found that the ACE1 II genotype frequency in a population was significantly negatively correlated with the number of SARS-CoV-2 cases. Similarly, the ACE1 II genotype was negatively correlated with the number of deaths due to SARS-CoV-2 infection. These data suggest that the ACE1 II genotype may influence the prevalence and clinical outcome of COVID-19 and serve as a predictive marker for COVID-19 risk and severity.
  • PT-Symmetric Absorber-Laser Enables Electromagnetic Sensors with Unprecedented Sensitivity

    Farhat, Mohamed; Yang, Minye; Ye, Zhilu; Chen, Pai-Yen (ACS Photonics, American Chemical Society (ACS), 2020-07-07) [Article]
    Achieving extraordinarily high sensitivity is a long-sought goal in the development of novel and more capable electromagnetic sensors. We present here how a coherent perfect absorber-laser (CPAL) enabled by parity-time (PT) symmetry breaking may be exploited to build ultrasensitive monochromatic electromagnetic sensors that use radio waves, microwaves, terahertz radiations, or light. We argue the possibility of using such CPAL sensors to detect extremely small-scale perturbations of admittance or refractive index caused by, for example, low-density gas molecules and microscopic properties, as they may drastically vary the system’s output intensity from very low (coherent absorption) to high (lasing). We derive the physical bounds on CPAL sensors, showing that their sensitivity and resolvability may go well beyond traditional electromagnetic sensors, such as sensors based on Fabry-Perot cavities.
  • Systematic Study on Morphological Development of Blade-Coated Conjugated Polymer Thin Films via In Situ Measurements

    Kim, Yeon-Ju; Lee, Sehyun; Niazi, Muhammad Rizwan; Hwang, Kyoungtae; Tang, Ming-Chun; Lim, Dae-Hee; Kang, Ji-Sue; Smilgies, Detlef-M.; Amassian, Aram; Kim, Dong-Yu (ACS Applied Materials & Interfaces, American Chemical Society (ACS), 2020-07-07) [Article]
    The morphology of conjugated polymer thin films, determined by the kinetics of film drying, is closely correlated with their electrical properties. Herein, we focused on dramatic changes in thin film morphology of blade-coated poly{[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} caused by the effect of solvent and coating temperature. Through in situ measurements the evolution of polymer aggregates and crystallites, which plays a decisive role in the formation of the charge transporting pathway, was observed in real-time. By combining in situ ultraviolet-visible spectroscopy and in situ grazing-incidence wide-angle X-ray scattering analysis, we could identify five distinct stages during the blade-coating process; these stages were observed irrespective of the solvent and coating temperature used. The five stages are described in detail with a proposed model of film formation. This insight is an important step in understanding the relationship between the morphology of thin polymer films and their charge-transport properties as well as optimizing the structural evolution of thin films.
  • Semiparametric estimation of cross-covariance functions for multivariate random fields

    Qadir, Ghulam A.; Sun, Ying (Biometrics, Wiley, 2020-07-06) [Article]
    The prevalence of spatially referenced multivariate data has impelled researchers to develop procedures for joint modeling of multiple spatial processes. This ordinarily involves modeling marginal and cross-process dependence for any arbitrary pair of locations using a multivariate spatial covariance function. However, building a flexible multivariate spatial covariance function that is nonnegative definite is challenging. Here, we propose a semiparametric approach for multivariate spatial covariance function estimation with approximate Matérn marginals and highly flexible cross-covariance functions via their spectral representations. The flexibility in our cross-covariance function arises due to B-spline based specification of the underlying coherence functions, which in turn allows us to capture non-trivial cross-spectral features. We then develop a likelihood-based estimation procedure and perform multiple simulation studies to demonstrate the performance of our method, especially on the coherence function estimation. Finally, we analyze particulate matter concentrations (PM2.5) and wind speed data over the West-North-Central climatic region of the United States, where we illustrate that our proposed method outperforms the commonly used full bivariate Matérn model and the linear model of coregionalization for spatial prediction.
  • Expression of a carotenogenic gene allows faster biomass production by redesigning plant architecture and improving photosynthetic efficiency in tobacco.

    Moreno, Juan C; Mi, Jianing; Agrawal, Shreya; Kössler, Stella; Turečková, Veronika; Tarkowská, Danuše; Thiele, Wolfram; Al-Babili, Salim; Bock, Ralph; Schöttler, Mark Aurel (The Plant journal : for cell and molecular biology, Wiley, 2020-07-06) [Article]
    Because carotenoids act as accessory pigments in photosynthesis, play a key photoprotective role, and are of major nutritional importance, carotenogenesis has been a target for crop improvement. Although carotenoids are important precursors of phytohormones, previous genetic manipulations reported little if any effects on biomass production and plant development, but resulted in specific modifications in carotenoid content. Unexpectedly, the expression of the carrot lycopene b-cyclase (DcLCYB1) in Nicotiana tabacum cv. Xanthi not only resulted in increased carotenoid accumulation, but also in altered plant architecture characterized by longer internodes, faster plant growth, early flowering and increased biomass. Here, we have challenged these transformants with a range of growth conditions to determine the robustness of their phenotype and analyze the underlying mechanisms. Transgenic DcLCYB1 lines showed increased transcript levels of key genes involved in carotenoid, chlorophyll, gibberellin (GA) and abscisic acid (ABA) biosynthesis, but also in photosynthesis-related genes. Accordingly, their carotenoid, chlorophyll, ABA and GA contents were increased. Hormone application and inhibitor experiments confirmed the key role of altered GA/ABA contents in the growth phenotype. Because the longer internodes reduce shading of mature leaves, induction of leaf senescence was delayed, and mature leaves maintained a high photosynthetic capacity. This increased total plant assimilation, as reflected in higher plant yields under both fully-controlled constant and fluctuating light, and in non-controlled conditions. Furthermore, our data is a warning that engineering of isoprenoid metabolism can cause complex changes in phytohormone homeostasis and therefore plant development, which have not been sufficiently considered in previous studies.
  • Unfamiliar partnerships limit cnidarian holobiont acclimation to warming

    Herrera Sarrias, Marcela; Klein, Shannon; Schmidt-Roach, Sebastian; Campana, Sara; Cziesielski, Maha Joana; Chen, Jit Ern; Duarte, Carlos M.; Aranda, Manuel (Global Change Biology, Wiley, 2020-07-06) [Article]
    Enhancing the resilience of corals to rising temperatures is now a matter of urgency, leading to growing efforts to explore the use of heat tolerant symbiont species to improve their thermal resilience. The notion that adaptive traits can be retained by transferring the symbionts alone, however, challenges the holobiont concept, a fundamental paradigm in coral research. Holobiont traits are products of a specific community (holobiont) and all its co-evolutionary and local adaptations, which might limit the retention or transference of holobiont traits by exchanging only one partner. Here, we evaluate how interchanging partners affect the short- and long-term performance of holobionts under heat stress using clonal lineages of the cnidarian model system Aiptasia (host and Symbiodiniaceae strains) originating from distinct thermal environments. Our results show that holobionts from more thermally variable environments have higher plasticity to heat stress, but this resilience could not be transferred to other host genotypes through the exchange of symbionts. Importantly, our findings highlight the role of the host in determining holobiont productivity in response to thermal stress and indicate that local adaptations of holobionts will likely limit the efficacy of interchanging unfamiliar compartments to enhance thermal tolerance.
  • Numerical Study of CH4 Generation and Transport in XLPE-Insulated Cables in Continuous Vulcanization

    Ruslan, Mohd Fuad Anwari Che; Youn, Dong Joon; Aarons, Roshan; Sun, Yabin; Sun, Shuyu (Materials, MDPI AG, 2020-07-06) [Article]
    <jats:p>In this work, we apply a computational diffusion model based on Fick’s laws to study the generation and transport of methane (CH 4 ) during the production of a cross-linked polyethylene (XLPE) insulated cable. The model takes into account the heating process in a curing tube where most of the cross-linking reaction occurs and the subsequent two-stage cooling process, with water and air as the cooling media. For the calculation of CH 4 generation, the model considers the effect of temperature on the cross-linking reaction selectivity. The cross-linking reaction selectivity is a measure of the preference of cumyloxy to proceed either with a hydrogen abstraction reaction, which produces cumyl alcohol, or with a β -scission reaction, which produces acetophenone and CH 4 . The simulation results show that, during cable production, a significant amount of CH 4 is generated in the XLPE layer, which diffuses out of the cable and into the conductor part of the cable. Therefore, the diffusion pattern becomes a non-uniform radial distribution of CH 4 at the cable take-up point, which corresponds well with existing experimental data. Using the model, we perform a series of parametric studies to determine the effect of the cable production conditions, such as the curing temperature, line speed, and cooling water flow rate, on CH 4 generation and transport during cable production. The results show that the curing temperature has the largest impact on the amount of CH 4 generated and its distribution within the cable. We found that under similar curing and cooling conditions, varying the line speed induces a notable effect on the CH 4 transport within the cable, while the cooling water flow rate had no significant impact.</jats:p>

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