Recent Submissions

  • The SWI/SNF chromatin remodeling factor DPF3 regulates metastasis of ccRCC by modulating TGF-β signaling

    Cui, Huanhuan; Yi, Hongyang; Bao, Hongyu; Tan, Ying; Tian, Chi; Shi, Xinyao; Gan, Diwen; Zhang, Bin; Liang, Weizheng; Chen, Rui; Zhu, Qionghua; Fang, Liang; Gao, Xin; Huang, Hongda; Tian, Ruijun; Sperling, Silke R.; Hu, Yuhui; Chen, Wei (Nature Communications, Springer Science and Business Media LLC, 2022-08-09) [Article]
    DPF3, a component of the SWI/SNF chromatin remodeling complex, has been associated with clear cell renal cell carcinoma (ccRCC) in a genome-wide association study. However, the functional role of DPF3 in ccRCC development and progression remains unknown. In this study, we demonstrate that DPF3a, the short isoform of DPF3, promotes kidney cancer cell migration both in vitro and in vivo, consistent with the clinical observation that DPF3a is significantly upregulated in ccRCC patients with metastases. Mechanistically, DPF3a specifically interacts with SNIP1, via which it forms a complex with SMAD4 and p300 histone acetyltransferase (HAT), the major transcriptional regulators of TGF-β signaling pathway. Moreover, the binding of DPF3a releases the repressive effect of SNIP1 on p300 HAT activity, leading to the increase in local histone acetylation and the activation of cell movement related genes. Overall, our findings reveal a metastasis-promoting function of DPF3, and further establish the link between SWI/SNF components and ccRCC.
  • Laser-Powered UAVs for Wireless Communication Coverage: A Large-Scale Deployment Strategy

    Lahmeri, Mohamed-Amine; Kishk, Mustafa A.; Alouini, Mohamed-Slim (IEEE Transactions on Wireless Communications, IEEE, 2022-08-09) [Article]
    The use of unmanned aerial vehicles (UAVs) is strongly advocated for sixth-generation (6G) networks, as the 6G standard will not be limited to improving broadband services, but will also target the extension of the geographical cellular coverage. In this context, the deployment of UAVs is considered a key solution for seamless connectivity and reliable coverage. That being said, it is important to underline that although UAVs are characterized by their high mobility and their ability to establish line-of-sight (LOS) links, their use is still impeded by several factors such as weather conditions, their limited computing power, and, most importantly, their limited energy. In this work, we are aiming for the novel technology that enables indefinite wireless power transfer for UAVs using laser beams. We propose a novel UAV deployment strategy, based on which we analyze the overall performance of the system in terms of wireless coverage. To this end, we use tractable tools from stochastic geometry to model the complex communication system. We analyze the user’s connectivity profile under different laser charging capabilities and in different type of environments. We show a decrease in the coverage probability by more than 12% in moderate-to-strong turbulence conditions compared to low turbulence conditions. We also show how the connection rate to the aerial network significantly decreases in favor of the terrestrial network for short laser charging ranges. We conclude that laser-powered drones are considered interesting alternatives when placed in LOS with users, in low-to-moderate optical turbulence, and at reasonable ranges from the charging stations.
  • PYK2 senses calcium through a disordered dimerization and calmodulin-binding element

    Momin, Afaque Ahmad Imtiyaz; Mendes, Tiago; Barthe, Philippe; Faure, Camille; Hong, Seungbeom; Yu, Piao; Kadaré, Gress; Jaremko, Mariusz; Girault, Jean Antoine; Jaremko, Lukasz; Arold, Stefan T. (Communications Biology, Springer Science and Business Media LLC, 2022-08-09) [Article]
    Multidomain kinases use many ways to integrate and process diverse stimuli. Here, we investigated the mechanism by which the protein tyrosine kinase 2-beta (PYK2) functions as a sensor and effector of cellular calcium influx. We show that the linker between the PYK2 kinase and FAT domains (KFL) encompasses an unusual calmodulin (CaM) binding element. PYK2 KFL is disordered and engages CaM through an ensemble of transient binding events. Calcium increases the association by promoting structural changes in CaM that expose auxiliary interaction opportunities. KFL also forms fuzzy dimers, and dimerization is enhanced by CaM binding. As a monomer, however, KFL associates with the PYK2 FERM-kinase fragment. Thus, we identify a mechanism whereby calcium influx can promote PYK2 self-association, and hence kinase-activating trans-autophosphorylation. Collectively, our findings describe a flexible protein module that expands the paradigms for CaM binding and self-association, and their use for controlling kinase activity.
  • Fast water transport and molecular sieving through ultrathin ordered conjugated-polymer-framework membranes

    Shen, Jie; Cai, Yichen; Zhang, Chenhui; Wei, Wan; Chen, Cailing; Liu, Lingmei; Yang, Kuiwei; Ma, Yinchang; Wang, Yingge; Tseng, Chien-Chih; Fu, Jui-Han; Dong, Xinglong; Li, Jiaqiang; Zhang, Xixiang; Li, Lain-Jong; Jiang, Jianwen; Pinnau, Ingo; Tung, Vincent; Han, Yu (Nature Materials, Springer Science and Business Media LLC, 2022-08-08) [Article]
    The development of membranes that block solutes while allowing rapid water transport is of great importance. The microstructure of the membrane needs to be rationally designed at the molecular level to achieve precise molecular sieving and high water flux simultaneously. We report the design and fabrication of ultrathin, ordered conjugated-polymer-framework (CPF) films with thicknesses down to 1 nm via chemical vapour deposition and their performance as separation membranes. Our CPF membranes inherently have regular rhombic sub-nanometre (10.3 × 3.7 Å) channels, unlike membranes made of carbon nanotubes or graphene, whose separation performance depends on the alignment or stacking of materials. The optimized membrane exhibited a high water/NaCl selectivity of ∼6,900 and water permeance of ∼112 mol m−2 h−1 bar−1, and salt rejection >99.5% in high-salinity mixed-ion separations driven by osmotic pressure. Molecular dynamics simulations revealed that water molecules quickly and collectively pass through the membrane by forming a continuous three-dimensional network within the hydrophobic channels. The advent of ordered CPF provides a route towards developing carbon-based membranes for precise molecular separation.
  • Secrecy Outage Performance Analysis of Dual-Hop RF-UOWC Systems

    Lei, Hongjiang; Zhu, Chen; Ansari, Imran Shafique; Park, Kihong; Pan, Gaofeng (IEEE Systems Journal, IEEE, 2022-08-08) [Article]
    This article investigates the secrecy performance of a dual-hop radio frequency-underwater optical wireless communication (RF-UOWC) system. Using stochastic geometry theory, the eavesdroppers are modeled as a Poisson point process distribution, and RF and UOWC links are modeled as Nakagami-m and mixture exponential-generalized gamma distributions, respectively. Firstly, we derive the statistical laws of signal-to-noise ratio for illegitimate receivers in both colluding and noncolluding scenarios and legitimate receivers when amplify-and-forward and decode-and-forward relaying strategies are employed. Subsequently, closed-form expressions for the lower bound of secrecy outage probability (SOP) are derived. Finally, analytical results are verified via Monte Carlo simulation results, and the effects of channel and system parameters on secrecy outage performance of dual-hop systems are analyzed. Numerical results demonstrate that environmental parameters, such as temperature and bubble levels, exhibit an important impact on the SOP of RF-UOWC systems.
  • Low-voltage ultrafast nonvolatile memory via direct charge injection through a threshold resistive-switching layer

    Li, Yuan; Zhang, Zhi Cheng; Li, Jiaqiang; Chen, Xu-Dong; Kong, Ya; Wang, Fu-Dong; Zhang, Guo-Xin; Lu, Tong-Bu; Zhang, Jin (Nature communications, Springer Science and Business Media LLC, 2022-08-06) [Article]
    The explosion in demand for massive data processing and storage requires revolutionary memory technologies featuring ultrahigh speed, ultralong retention, ultrahigh capacity and ultralow energy consumption. Although a breakthrough in ultrafast floating-gate memory has been achieved very recently, it still suffers a high operation voltage (tens of volts) due to the Fowler-Nordheim tunnelling mechanism. It is still a great challenge to realize ultrafast nonvolatile storage with low operation voltage. Here we propose a floating-gate memory with a structure of MoS2/hBN/MoS2/graphdiyne oxide/WSe2, in which a threshold switching layer, graphdiyne oxide, instead of a dielectric blocking layer in conventional floating-gate memories, is used to connect the floating gate and control gate. The volatile threshold switching characteristic of graphdiyne oxide allows the direct charge injection from control gate to floating gate by applying a nanosecond voltage pulse (20 ns) with low magnitude (2 V), and restricts the injected charges in floating gate for a long-term retention (10 years) after the pulse. The high operation speed and low voltage endow the device with an ultralow energy consumption of 10 fJ. These results demonstrate a new strategy to develop next-generation high-speed low-energy nonvolatile memory.
  • Investigating calcification-related candidates in a non-symbiotic scleractinian coral, Tubastraea spp.

    Capasso, Laura; Aranda, Manuel; Cui, Guoxin; Pousse, Melanie; Tambutté, Sylvie; Zoccola, Didier (Scientific Reports, Springer Science and Business Media LLC, 2022-08-06) [Article]
    In hermatypic scleractinian corals, photosynthetic fixation of CO2 and the production of CaCO3 are intimately linked due to their symbiotic relationship with dinoflagellates of the Symbiodiniaceae family. This makes it difficult to study ion transport mechanisms involved in the different pathways. In contrast, most ahermatypic scleractinian corals do not share this symbiotic relationship and thus offer an advantage when studying the ion transport mechanisms involved in the calcification process. Despite this advantage, non-symbiotic scleractinian corals have been systematically neglected in calcification studies, resulting in a lack of data especially at the molecular level. Here, we combined a tissue micro-dissection technique and RNA-sequencing to identify calcification-related ion transporters, and other candidates, in the ahermatypic non-symbiotic scleractinian coral Tubastraea spp. Our results show that Tubastraea spp. possesses several calcification-related candidates previously identified in symbiotic scleractinian corals (such as SLC4-γ, AMT-1like, CARP, etc.). Furthermore, we identify and describe a role in scleractinian calcification for several ion transporter candidates (such as SLC13, -16, -23, etc.) identified for the first time in this study. Taken together, our results provide not only insights about the molecular mechanisms underlying non-symbiotic scleractinian calcification, but also valuable tools for the development of biotechnological solutions to better control the extreme invasiveness of corals belonging to this particular genus.
  • Topochemical Synthesis of Ca3CrN3H Involving a Rotational Structural Transformation for Catalytic Ammonia Synthesis

    Cao, Yu; Kirsanova, Maria; Ochi, Masayuki; Almaksoud, Walid; Zhu, Tong; Rai, Rohit Kumar; Gao, Shenghan; Tsumori, Tatsuya; Kobayashi, Shintaro; Kawaguchi, Shogo; Abou-Hamad, Edy; Kuroki, Kazuhiko; Tassel, Cédric; Abakumov, Artem; Kobayashi, Yoji; Kageyama, Hiroshi (Angewandte Chemie (International ed. in English), Wiley, 2022-08-05) [Article]
    Topochemical reactions have led to great progress in the discovery of new metastable compounds with novel chemical and physical properties. With these reactions, the overall crystal structure of the host material is generally maintained. Here we report a topochemical synthesis of a hexagonal nitride hydride, h-Ca3CrN3H, by heating an orthorhombic nitride, o-Ca3CrN3, under hydrogen at 673 K, accompanied by a rotational structural transformation. The hydrogen intercalation modifies the Ca-N rock-salt-like atomic packing in o-Ca3CrN3 to a face-sharing octahedral chain in h-Ca3CrN3H, mimicking a 'hinged tessellation' movement. In addition, the h-Ca3CrN3H exhibited stable ammonia synthesis activity when used as a catalyst.
  • Study of the Seawater Desalination Performance by Electrodialysis

    Shi, Jihong; Gong, Liang; Zhang, Tao; Sun, Shuyu (Membranes, MDPI AG, 2022-08-05) [Article]
    The global scarcity of freshwater resources has greatly contributed to the development of desalination technologies, in which electrodialysis desalination is one of the most widely used and highly regarded methods. In this work, the first step was to design and assemble a experiment module for electrodialysis desalination. The ion removal efficiency and single membrane mass transfer flux of electrodialysis desalination were investigated. The results show that the desalination performance of the module is improved by increasing the voltage gradient, increasing the concentration of seawater and electrolyte and decreasing the membrane surface flux and that the optimum operating conditions for the module at 24 V operating voltage are feedstock concentration of 35 g/L, electrolyte concentration of 1.42 g/L which and system flow rate of 15 L/h. The results of the study will help to better investigate electrodialysis desalination technology.
  • Spectrochemistry of Firefly Bioluminescence

    Al-Handawi, Marieh B.; Polavaram, Srujana; Kurlevskaya, Anastasiya; Commins, Patrick; Schramm, Stefan; Carrasco-López, César; Lui, Nathan M.; Solntsev, Kyril M.; Laptenok, Siarhei; Navizet, Isabelle; Naumov, Panče (Chemical Reviews, American Chemical Society (ACS), 2022-08-04) [Article]
    The chemical reactions underlying the emission of light in fireflies and other bioluminescent beetles are some of the most thoroughly studied processes by scientists worldwide. Despite these remarkable efforts, fierce academic arguments continue around even some of the most fundamental aspects of the reaction mechanism behind the beetle bioluminescence. In an attempt to reach a consensus, we made an exhaustive search of the available literature and compiled the key discoveries on the fluorescence and chemiluminescence spectrochemistry of the emitting molecule, the firefly oxyluciferin, and its chemical analogues reported over the past 50+ years. The factors that affect the light emission, including intermolecular interactions, solvent polarity, and electronic effects, were analyzed in the context of both the reaction mechanism and the different colors of light emitted by different luciferases. The collective data points toward a combined emission of multiple coexistent forms of oxyluciferin as the most probable explanation for the variation in color of the emitted light. We also highlight realistic research directions to eventually address some of the remaining questions related to firefly bioluminescence. It is our hope that this extensive compilation of data and detailed analysis will not only consolidate the existing body of knowledge on this important phenomenon but will also aid in reaching a wider consensus on some of the mechanistic details of firefly bioluminescence.
  • High Performance Micro Resonators-based Sensors using Multi-Mode Excitation

    Zhao, Wen; Khan, Fahimullah; Alcheikh, Nouha; Younis, Mohammad I. (IEEE Electron Device Letters, Institute of Electrical and Electronics Engineers (IEEE), 2022-08-04) [Article]
    We present a multi-mode excitation technique to significantly amplify the amplitude signal of micro-resonators-based sensors operating at their higher-order modes. We show that the multi-mode excitation can significantly reduce the noise effects, elevate the dynamic response level, and amplify the total amplitude response. We demonstrate the efficiency of the multi-mode excitation to enhance the performance of a gas sensor using electrothermally heated doubly-clamped buckled beams. The results indicate clear amplification for the response at the 2nd mode while detecting Helium compared to a single-source excitation. A 24-times amplitude magnification is achieved. The demonstrated approach provides a promising path to efficiently exploit the higher-order modes of resonant gas sensors leading to improved accuracy and resolution.
  • Single-step post-production treatment of lead acetate precursor-based perovskite using alkylamine salts for reduced grain-boundary related film defects

    Gebremichael, Zekarias Teklu; Alam, Shahidul; Stumpf, Steffi; Diegel, Marco; Schubert, Ulrich S.; Hoppe, Harald (Nano Select, Wiley, 2022-08-04) [Article]
    Powered by the worldwide efforts of research groups experienced in dye-sensitized, and thin-film solar cells, perovskite solar cells (PSCs) reached a power conversion efficiency of 25.7% within 10 years. However, the presence of defects and trap density within the active layer's grain boundaries commonly operates as non-radiative recombination centers. Hence, intensive efforts have been reported to passivate the inevitable bulk and interface defects of the active layer using additives or post-treatment processing to enhance the efficiency and stability of PSCs. Herein, a facile post-treatment strategy based on wet processing methylammonium lead triiodide, MAPbI3 (prepared from lead acetate and methylammonium iodide precursors) films with organic amine salts (FABr and FAI) is demonstrated. As a result, high-quality films of mixed perovskites (FAxMA1-xPbI3-xBrx and FAxMA1-xPbI3) were obtained. The surface treatment has efficiently passivate the defects in the host film, suppressing the non-radiative carrier recombination. Compared to the control device, the increased open-circuit voltage (from 0.5 V to 1 V) and fill factor (FF) values of the optimized device based on FAxMA1-xPbI3 showed a PCE of 16.13%. And our findings revealed that post-treatment is possible on wet perovskite film aged for a few minutes prior to its post-treatment, which saved the energy used for pre-annealing.
  • Prevalence of anti-SARS-CoV-2 antibody in hemodialysis facilities: a cross-sectional multicenter study from Madinah

    Housawi, Abdulrahman A.; Qazi, Shazada Junaid S.; Jan, Abdulhalem A.; Osman, Rashid A.; Alshamrani, Mashil M.; AlFaadhel, Talal A.; AlHejaili, Fayez F.; Al-Tawfiq, Jaffar A.; Wafa, Ahmed A.; Hamza, Abdulmageed E.; Hassan, Moustafa A.; Alharbi, Suliman A.; Albasheer, Hamza; Almohmmdi, Majed M.; Alsisi, Salem A.; Mankowski, Michal; van de Klundert, Joris; Alhelal, Amal M.; Sala, Fatima H.; Kheyami, Ali; Alhomayeed, Bader A. (Annals of Saudi Medicine, King Faisal Specialist Hospital and Research Centre, 2022-08-04) [Article]
    BACKGROUND: Since the occurrence of coronavirus disease in 2019 (COVID-19), the global community has witnessed its exponential spread with devastating outcomes within the general population and specifically within hemodialysis patients. OBJECTIVES: Compare the state of immunity to SARS-CoV-2 among hemodialysis patients and staff. DESIGN: Cross-sectional study with a prospective follow-up period. SETTING: Hemodialysis centers in Madinah region. PATIENTS AND METHODS: We prospectively tested for SARS-CoV-2 antibodies in dialysis patients using dialysis centers staff as controls. The participants were tested on four occasions when feasible for the presence of anti-SARS-CoV-2 antibodies. We also analyzed factors that might be associated with seropositivity. MAIN OUTCOME MEASURES: SARS-CoV-2 positivity using immunoglobulin G (IgG) levels SAMPLE SIZE: 830 participants, 677 patients and 153 dialysis centers staff as controls. RESULTS: Of the total participants, 325 (257 patients and 68 staff) were positive for SARS-CoV-2 IgG antibodies, for a prevalence of 38.0% and 44.4% among patients and staff, respectively (P=.1379). Participants with a history of COVID-19 or related symptoms were more likely to have positive IgG (P<.0001). Surprisingly, positivity was also center-dependent. In a multivariable logistic regression, a history of infection and related symptoms contributed significantly to developing immunity. CONCLUSION: The high prevalence of SARS-CoV-2 antibody among hemodialysis patients and previously asymptomatic staff suggested past asymptomatic infection. Some centers showed more immunity effects than others. LIMITATIONS: Unable to collect four samples for each participant; limited to one urban center. CONFLICT OF INTEREST: None.
  • A new species of Bathypathes (Cnidaria, Anthozoa, Antipatharia, Schizopathidae) from the Red Sea and its phylogenetic position

    Chimienti, Giovanni; Terraneo, Tullia Isotta; Vicario, Silvia; Marchese, Fabio; Purkis, Sam J.; Abdulla Eweida, Ameer; Rodrigue, Mattie; Benzoni, Francesca (ZooKeys, Pensoft Publishers, 2022-08-04) [Article]
    A black coral, Bathypathes thermophila Chimienti, sp. nov. is described from the Saudi Arabian coasts of the Gulf of Aqaba and north Red Sea (Neom area) using an integrated taxonomic approach. The morphological distinctiveness of the new species is confirmed by molecular analyses. The species thrives in warm and high salinity waters typical of the Red Sea at bathyal depths. It can form colony aggregations on muddy bottoms with scattered, small hard substrates. Colonies are monopodial, feather-like, and attached to a hard substrate through a thorny basal plate. Pinnules are simple, arranged biserially and alternately, and all the same length (up to approximately 20 cm) except for few, proximal ones. Spines are triangular, laterally compressed, subequal, smooth, and simple or rarely bifurcated. Polyps are elongated transversely, 1.5–2.0 mm in transverse diameter. Large colonies can have one or few branches, whose origin is discussed. The phylogenetic position of B. thermophila sp. nov. within the order Antipatharia, recovered using three mitochondrial markers, shows that it is nested within the family Schizopathidae. It is close to species in the genera Parantipathes, Lillipathes, Alternatipathes, and Umbellapathes rather than to the other available representatives of the genus Bathypathes, as currently defined based on morphology. In agreement with previous findings, our results question the evolutionary significance of morphological characters traditionally used to discriminate Antipatharia at higher taxonomic level.
  • Beamforming Design for Integrated Sensing and Communication Systems with Finite Alphabet Input

    Cong, Dingyan; Guo, Shuaishuai; Zhang, Haixia; Ye, Jia; Alouini, Mohamed-Slim (IEEE Wireless Communications Letters, IEEE, 2022-08-04) [Article]
    Joint beamforming for integrated sensing and communication (ISAC) is an efficient way to combine two functionalities in a system at the waveform level. This letter proposes a beamforming design for ISAC systems with finite alphabet signaling. We formulate a problem to maximize the minimum Euclidean distance (MMED) among noise-free received signal vectors under a sensing constraint and a given power constraint. To tackle the formulated optimization problem, we transform it into a semi-definite programming (SDP) and solve it by the semi-definite relaxation (SDR) method. Comprehensive comparisons with existing schemes show that our proposed beamforming offers lower symbol error rate (SER), higher mutual information, and also better sensing performance than existing ISAC beamforming designs.
  • Immunoinformatics-Aided Design and In Vivo Validation of a Peptide-Based Multiepitope Vaccine Targeting Canine Circovirus

    Kaushik, Vikas; Jain, Pankaj; Akhtar, Nahid; Joshi, Amit; Gupta, Lovi Raj; Grewal, Ravneet Kaur; Oliva, Romina; Shaikh, Abdul Rajjak; Cavallo, Luigi; Chawla, Mohit (ACS Pharmacology & Translational Science, American Chemical Society (ACS), 2022-08-03) [Article]
    Canine circovirus (CanineCV) is a deadly pathogen affecting both domestic and wild carnivores including dogs. No vaccine against CanineCV is available commercially or under clinical trials. In the present study, we have designed a promising multiepitope vaccine (MEV) construct targeting multiple strains of CanineCV. A total of 545 MHCII binding CD4+T cell epitope peptides were predicted from the capsid and replicase protein from each strain of CanineCV. Five conserved epitope peptides among the three CanineCV strains were selected. The final vaccine was constructed using antigenic, nontoxic, and conserved multiple epitopes identified in silico. Further, molecular docking and molecular dynamics simulations predicted stable interactions between the predicted MEV and canine receptor TLR-5. To validate antigenicity and immunogenicity, one of the mapped epitope peptides was synthesized. In vivo analysis of the selected epitope clearly indicates CD4+T-cell-dependent generation of antibodies which further suggests that the designed MEV construct holds promise as a candidate for vaccine against CanineCV.
  • Conditional Contact Angle Distribution in LEO Satellite-Relayed Transmission

    Wang, Ruibo; Talgat, Anna; Kishk, Mustafa Abdelsalam; Alouini, Mohamed-Slim (IEEE Communications Letters, Institute of Electrical and Electronics Engineers (IEEE), 2022-08-03) [Article]
    This letter characterizes the contact angle distribution based on the condition that the relay low earth orbit (LEO) satellite is in the communication range of both the ground transmitter and the ground receiver. As one of the core distributions in stochastic geometry-based routing analysis, the analytical expression of the Cumulative Distribution Function (CDF) of the conditional contact angle is derived. Furthermore, the conditional contact angle is applied to analyze the inaccessibility of common satellites between the ground transmitter and receiver. Finally, with the help of the conditional contact angle, coverage probability and achievable data rate in LEO satellite-relayed transmission are studied.
  • Ocean Warming Amplifies the Effects of Ocean Acidification on Skeletal Mineralogy and Microstructure in the Asterinid Starfish Aquilonastra yairi

    Khalil, Munawar; Doo, Steve S.; Stuhr, Marleen; Westphal, Hildegard (Journal of Marine Science and Engineering, MDPI AG, 2022-08-03) [Article]
    Ocean acidification and ocean warming compromise the capacity of calcifying marine organisms to generate and maintain their skeletons. While many marine calcifying organisms precipitate low-Mg calcite or aragonite, the skeleton of echinoderms consists of more soluble Mg-calcite. To assess the impact of exposure to elevated temperature and increased pCO2 on the skeleton of echinoderms, in particular the mineralogy and microstructure, the starfish Aquilonastra yairi (Echinodermata: Asteroidea) was exposed for 90 days to simulated ocean warming (27 °C and 32 °C) and ocean acidification (455 µatm, 1052 µatm, 2066 µatm) conditions. The results indicate that temperature is the major factor controlling the skeletal Mg (Mg/Ca ratio and Mgnorm ratio), but not for skeletal Sr (Sr/Ca ratio and Srnorm ratio) and skeletal Ca (Canorm ratio) in A. yairi. Nevertheless, inter-individual variability in skeletal Sr and Ca ratios increased with higher temperature. Elevated pCO2 did not induce any statistically significant element alterations of the skeleton in all treatments over the incubation time, but increased pCO2 concentrations might possess an indirect effect on skeletal mineral ratio alteration. The influence of increased pCO2 was more relevant than that of increased temperature on skeletal microstructures. pCO2 as a sole stressor caused alterations on stereom structure and degradation on the skeletal structure of A. yairi, whereas temperature did not; however, skeletons exposed to elevated pCO2 and high temperature show a strongly altered skeleton structure compared to ambient temperature. These results indicate that ocean warming might exacerbate the skeletal maintaining mechanisms of the starfish in a high pCO2 environment and could potentially modify the morphology and functions of the starfish skeleton.
  • Coverage Enhancement of Underwater Internet of Things Using Multi-Level Acoustic Communication Networks

    Xu, Jiajie; Kishk, Mustafa Abdelsalam; Alouini, Mohamed-Slim (IEEE Internet of Things Journal, Institute of Electrical and Electronics Engineers (IEEE), 2022-08-03) [Article]
    Underwater acoustic communication networks (UACNs) are considered a key-enabler to the underwater internet of things (UIoT). UACN is regarded as essential for various marine applications such as monitoring, exploration, and trading. However, a large part of existing literature disregards the 3-dimensional (3D) nature of the underwater communication system. In this paper, we propose a K-tier UACN that acts as a gateway that connects the UIoT with the Space-Air-Ground-Sea Integrated System (SAGSIS). The proposed network architecture consists of several tiers along the vertical direction with adjustable depths. On the horizontal dimension, the best coverage probability (CP) is computed and maximized by optimizing the densities of surface stations (SSs) in each tier. On the vertical dimension, the depth of each tier is also optimized to minimize inter-tier interference and maximize overall system performance. Using tools from stochastic geometry, the total CP of the proposed K-tier network is analyzed. For given spatial distribution of UIoT device’s depth, the best CP can be achieved by optimizing the depths of the transceivers connected to the SSs through a tether. We verify the accuracy of the analysis using Monte-Carlo simulations. In addition, we draw multiple useful system-level insights that help optimize the design of underwater 3D networks based on the given distribution of UIoT device’s depths.
  • Differential role of neuronal glucose and PFKFB3 in memory formation during development

    Cruz, Emmanuel; Bessières, Benjamin; Magistretti, Pierre J.; Alberini, Cristina M (Glia, 2022-08-02) [Article]
    The consumption of glucose in the brain peaks during late childhood; yet, whether and how glucose metabolism is differentially regulated in the brain during childhood compared to adulthood remains to be understood. In particular, it remains to be determined how glucose metabolism is involved in behavioral activations such as learning. Here we show that, compared to adult, the juvenile rat hippocampus has significantly higher mRNA levels of several glucose metabolism enzymes belonging to all glucose metabolism pathways, as well as higher levels of the monocarboxylate transporters MCT1 and MCT4 and the glucose transporters endothelial-GLUT1 and GLUT3 proteins. Furthermore, relative to adults, long-term episodic memory formation in juvenile animals requires significantly higher rates of aerobic glycolysis and astrocytic-neuronal lactate coupling in the hippocampus. Only juvenile but not adult long-term memory formation recruits GLUT3, neuronal 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and more efficiently engages glucose in the hippocampus. Hence, compared to adult, the juvenile hippocampus distinctively regulates glucose metabolism pathways, and formation of long-term memory in juveniles involves differential neuronal glucose metabolism mechanisms.

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