bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen-based technologies in maritime sector: technical analysis and prospective
Authors: Minutillo Mariagiovanna , Cigolotti Viviana , Di Ilio Giovanni , Bionda Arianna , Boonen Erik-Jan , Wannemacher Thomas
Published: January 2022

The maritime transportation sector is one of the main contributors to global emissions of greenhouse gases (GHGs). The International Maritime Organization (IMO) has adopted a strategy to reduce these emissions from international shipping >50% by 2050, compared to 2008’s emissions. Therefore, ship owners need to adopt solutions to bring emissions within these and other future limits by means of environmentally friendly fuels (hydrogen or hydrogen carriers) and high efficiency propulsion technologies (fuel cells). This paper focuses on the replacement of the conventional Diesel genset installed on a hybrid small-size ferry, with an innovative system based on PEMFC technology. A real case scenario is investigated: the total energy/power demand of the vessel is determined basing on a typical operational profile. Then, a preliminary redesign of its powertrain configuration is proposed along with an energy management strategy. The analysis has allowed to define the hydrogen consumption for a daily operation. Finally, different storage technologies involving both compressed and liquefied hydrogen have been considered and compared, in order to identify ship’s weight and space requirements.
Development of a plug-in fuel cell electric scooter with thermally integrated storage system based on hydrogen in metal hydrides and battery pack
Authors: Di Giorgio Paolo , Scarpati Gabriele , Di Ilio Giovanni , Arsie Ivan , Jannelli Elio
Published: January 2022

The thermal management of lithium-ion batteries in hybrid electric vehicles is a key issue, since operating temperatures can greatly affect their performance and life. A hybrid energy storage system, composed by the integration of a battery pack with a metal hydride-based hydrogen storage system, might be a promising solution, since it allows to efficiently exploit the endothermic desorption process of hydrogen in metal hydrides to perform the thermal management of the battery pack. In this work, starting from a battery electric scooter, a new fuel cell/battery hybrid powertrain is designed, based on the simulation results of a vehicle dynamic model that evaluates power and energy requirements on a standard driving cycle. Thus, the design of an original hybrid energy storage system for a plug-in fuel cell electric scooter is proposed, and its prototype development is presented. To this aim, the battery pack thermal power profile is retrieved from vehicle simulation, and the integrated metal hydride tank is sized in such a way to ensure a suitable thermal management. The conceived storage solution replaces the conventional battery pack of the vehicle. This leads to a significant enhancement of the on-board gravimetric and volumetric energy densities, with clear advantages on the achievable driving range. The working principle of the novel storage system and its integration within the powertrain of the vehicle are also discussed.
The different behaviour of Thermotoga neapolitana in the anodic and cathodic compartment of a bioelectrochemical system
Authors: Cristiani Pierangela , Malavola Laura , Franz Silvia , Bestetti Massimiliano , D’Ippolito Giuliana , Esercizio Nunzia , Lanzilli Mariamichela , Fontana Angelo
Published: January 2022

Thermotoga neapolitana is a hyperthermophilic bacterium that can metabolize glucose and several organic wastes in hydrogen and lactate at a temperature of 80°C. Their high performance in producing hydrogen at so high a temperature as 80°C suggests a potential energy application of them where hydrogen is an important element of the process. In this view, experimentation of a T.neapolitana strain is carried out in double-chamber electrochemical systems. The aim is to explore the interaction of these bacteria with the anode and the cathode, stressing their capability to survive in presence of a polarized electrode which can drastically change the pH of the media. A culture enriched of 5 g/L of glucose, under CO2 pressure (80 °C) was used to fill both the anodic and cathodic compartments of the electrochemical system, applying a voltage of 1.5 V between the anode and the cathode. The test lasted ten days. Results clearly indicate that bacteria colonize both electrodes, but the glucose metabolism is completely inhibited in the anodic compartments. On the contrary, metabolism is stimulated in the cathodic compartment. Bacteria are alive on the electrodes in the pH interval of 3 - 9.
Seltene Ursache eines Lungentumors – Fallbericht einer pulmonalen Infektion mit Hafnia alvei
Authors: Briegel Ignaz , Trautnitz Michael , Behr Jürgen
Published: January 2022

Bei Verdacht auf maligne Erkrankung ist die rasche Abklärung tumorverdächtiger pulmonaler Raumforderungen geboten. Im vorgestellten Fall gelang mehrmals kein Nachweis von Malignität. Erst die testgerechte antibiotische Behandlung eines inital als Verunreinigung gewerteten Darmkeimes brachte den Therapieerfolg mit Totalremission. Hierbei war die Behandlung mit dem Breitspektrumpenicillin Piperacillin/Tazobactam ineffektiv und erst die Gyrasehemmer Ciprofloxacin bzw. Levofloxacin brachten den Therapieerfolg.
Highly Enantioselective Michael Addition of Cyclic Diketones to β,γ-Unsaturated α-Keto Esters Catalyzed by Squaramide Organocatalyst
Authors: Ma Zhi-Wei , Wang Chuan-Chuan , Lv Quan-Jian , Chen Xiao-Pei , Li Ai-Qin , Tao Jing-Chao
Published: January 2022

A new tertiary amine-squaramide organocatalyst has been developed and applied to the asymmetric Michael addition of cyclic diketones to β,γ-unsaturated α-keto esters. The catalyst system performed well with a low catalyst loading of 1 mol% under mild reaction conditions. A series of synthetically and pharmaceutically useful chiral bicyclic compounds were obtained in high yields (up to 97%) with excellent enantioselectivities (up to 99 % ee). Furthermore, this catalytic system can be used efficiently in large-scale reactions with the yields and enantioselectivities being maintained.
Synthesis and Molecular Docking Studies of N,N-Dimethyl Arylpyranopyrimidinedione Derivatives
Authors: Velmathi Sivan , Prabhakaran Srinivasan
Published: January 2022

The synthesis of N,N-dimethyl arylpyranopyrimidinedione derivatives from aromatic aldehydes, N-methyl-1-(methylthio)-2-nitroethamine (NMSM) and 1,3-dimethyl barbituric acid, in the presence of piperidine as a catalyst, is reported. The reaction mechanism involves a Knoevenagel condensation, followed by Michael addition and intramolecular O-cyclization reaction sequence. The synthesized compounds were docked with human kinesin Eg5 protein to calculate binding energy, inhibition constant and H-bond interaction. All the compounds show good binding affinity towards the protein, with significant docking score.
Comparison of Collagen and Human Amniotic Membrane Nerve Wraps and Conduits for Peripheral Nerve Repair in Preclinical Models: A Systematic Review of the Literature
Authors: Wolfe Erin M. , Mathis Sydney A. , Ovadia Steven A. , Panthaki Zubin J.
Published: January 2022

Background Collagen and human amniotic membrane (hAM) are Food and Drug Administration (FDA)-approved biomaterials that can be used as nerve wraps or conduits for repair of peripheral nerve injuries. Both biomaterials have been shown to reduce scarring and fibrosis of injured peripheral nerves. However, comparative advantages and disadvantages have not been definitively shown in the literature. The purpose of this systematic review is to comprehensively evaluate the literature regarding the roles of hAM and collagen nerve wraps and conduits on peripheral nerve regeneration in preclinical models.

Methods The MEDLINE database was queried using the PubMed search engine on July 7, 2019, with the following search strategy: (“amniotic membrane” OR “amnion”) OR (“collagen conduit” OR “nerve wrap”)] AND “nerve.” All resulting articles were screened by two independent reviewers. Nerve type, lesion type/injury model, repair type, treatment, and outcomes were assessed.

Results Two hundred and fifty-eight articles were identified, and 44 studies remained after application of inclusion and exclusion criteria. Seventeen studies utilized hAM, whereas 27 studies utilized collagen wraps or conduits. Twenty-three (85%) of the collagen studies utilized conduits, and four (15%) utilized wraps. Six (35%) of the hAM studies utilized conduits and 11 (65%) utilized wraps. Two (9%) collagen studies involving a conduit and one (25%) involving a wrap demonstrated at least one significant improvement in outcomes compared with a control. While none of the hAM conduit studies showed significant improvements, eight (73%) of the studies investigating hAM wraps showed at least one significant improvement in outcomes.

Conclusion The majority of studies reported positive outcomes, indicating that collagen and hAM nerve wraps and conduits both have the potential to enhance peripheral nerve regeneration. However, relatively few studies reported significant findings, except for studies evaluating hAM wraps. Preclinical models may help guide clinical practice regarding applications of these biomaterials in peripheral nerve repair.
Percutaneous Vertebroplasty: Efficacy of Unipedicular Vertebroplasty as Compared to Bipedicular Vertebroplasty
Authors: Dwivedi Mahendra Kumar , Bhende Vikrant , Panchbhaiyye Dnyaneshwar Narayanrao , Bayaskar Madhura Vijay
Published: January 2022

Introduction Percutaneous vertebroplasty has been used for treatment of intractable painful fractures of vertebral bodies. With the help of refined procedures and standard techniques, the interventional radiologist can now offer help to orthopedics and neurosurgeons in these cases, which include treatment of vertebral compression fracture. Vertebroplasty is aimed at reducing the pain induced by collapse. Vertebroplasty is the standard mode of treatment for vertebral collapse, and in our study, bipedicular vertebroplasty was compared with unipedicular approach as bipedicular vertebroplasty is the routinely used approach.

Aim To compare efficacy of unipedicular percutaneous vertebroplasty with that of bipedicular percutaneous vertebroplasty.

Material and Methods A total of 52 vertebroplasties were done over a period of 2 years. Out of 52 patients, 28 patients underwent unipedicular vertebroplasty and 24 patients underwent bipedicular vertebroplasty. Visual analogue scale (VAS) scores were used to assess the pain prior to vertebroplasty and after vertebroplasty. Efficacy of the two procedures were assessed by comparing VAS scores.

Results There was no statistically significant difference observed in the preprocedure and postprocedure VAS scores (p-value < 0.0001, < 0.0001, respectively). The mean procedure time was lesser in unipedicular vertebroplasty (41.9 ± 3.90) than bipedicular vertebroplasty (54.5 ± 3.4).

Conclusion Unipedicular vertebroplasty is as effective as bipedicular vertebroplasty, as there is insignificant difference in postprocedure VAS scores between the unipedicular and bipedicular vertebroplasty.
Nasosinusal Endoscopic Anatomy and Physiology
Authors: Simoncello Lívia Miotta , Antonio Gabriel Farias , Pereira Barbara Casalecchi , Portela Júnior Estevan Martin , Silva Marcelo Nery
Published: January 2022

The present article focuses on the analysis of the nasal cavity's anatomy succinctly and descriptively. This essay was carried out through a bibliographic review, directed to the detailed anatomy of the nasal cavity, and the structures that form its sinuses. We have identified the need for more studies directed to the related anatomical area so that the improved knowledge of this region ensures a nasoendoscopic treatment with better effectiveness and no complications.
Sinonasal Neuroendocrine Carcinoma: 15 Years of Experience at a Single Institution
Authors: Keilin Charles A. , VanKoevering Kyle K. , McHugh Jonathan B. , McKean Erin L.
Published: January 2022

Objectives Sinonasal neuroendocrine carcinomas (SNECs) are among the rarest paranasal sinus cancers. Consensus guidelines for therapy are difficult to develop due to limited data regarding the natural history and successful treatment of these tumors. This study presents 15 years of experience treating SNEC at a single institution and a review of the literature.

Design Retrospective review.

Setting Academic medical center in the United States.

Participants Patients diagnosed with primary SNEC.

Main Outcome Measures Overall survival.

Results Thirteen patients were identified and included. Overall estimated survival was 74.6% at 5 years. Ten of 13 (76.9%) patients were diagnosed with high-grade neuroendocrine carcinoma and three (23.1%) with intermediate or low grade. All three patients with low- or intermediate-grade cancer survived more than 10 years from their initial diagnosis (median survival: 11.6 years) and are currently alive. The four patients who died had high-grade carcinoma, and estimated overall 5-year survival for all patients with high-grade carcinomas was 65.6%. Five patients, all with high-grade carcinoma, of seven who completed primary chemoradiation therapy (CRT) required salvage resection, and 60% are alive without disease.

Conclusion This cohort has a higher overall rate of survival than many recent case series and reviews. There is consensus that multimodal therapy is preferred over monotherapy, but approaches to treatment vary widely. Our approach of surgical resection as primary therapy for low-grade tumors and primary CRT for high-grade SNEC has been successful, and could indicate hope for improved survival among these patients.
Evolution in Sinonasal Mucosal Melanoma Management
Authors: Richa Tony , Lee Alice , Cohen Marc A.
Published: January 2022

Sinonasal mucosal melanoma is a rare and aggressive cancer with poor prognosis. Surgical resection with clear margins, when possible, remains the treatment of choice. Radiation therapy is generally used in the adjuvant setting with improved rates of local control following complete resection. Traditional chemotherapeutic agents do not improve the rates of locoregional control or survival. Immunotherapy has been used with some responders but with overall relatively poor outcomes. These outcomes highlight the need for new agents and more prospective trials in this space. We provide a unique case report of a patient with an advanced sinonasal mucosal melanoma and an overview of the recent literature pertaining to the management of this disease.
Necrotizing Enterocolitis in a Dutch Cohort of Very Preterm Infants: Prevalence, Mortality, and Long-Term Outcomes
Authors: Imren Ceren , Vlug Lotte E. , de Koning Barbara A. E. , Diertens Tessa , Snel Heleen E. , Suurland Jill , Swarte Renate M. C. , Vermeulen Marijn J. , Keyzer-Dekker Claudia M. G.
Published: January 2022

Introduction To improve counseling of parents and to guide care strategies, we studied the disease course and outcomes of necrotizing enterocolitis (NEC) up to 2 years of corrected age (CA) from a multidisciplinary perspective.

Materials and Methods This was a retrospective cohort study in preterm infants (birth weight < 1,500 g, gestational age < 32 weeks), diagnosed with NEC (Bell's stage ≥ II) from 2008 through 2020. Data on prevalence, mortality, surgery, intestinal failure (IF), growth, and neurodevelopment at 2-year follow-up were separately analyzed for medically and surgically treated children.

Results Of 3,456 preterm infants, 200 (6%) were diagnosed with NEC, of whom 135 developed an indication for surgery within 7 days after the diagnosis; 28/135 died before surgery, and 37/107 died after an open-and-close procedure. An enterostomy was constructed in 62 patients and an end-to-end anastomosis in 15. The postoperative course was described for 77 patients, of whom 23 developed surgical complications (12/23 incisional hernias, 9/23 anastomotic strictures), 13/77 a short bowel, and 25/77 IF. Sixty-day survival after birth for medical NEC patients was 88% (hazard ratio [HR]: 0.698; p = 0.318), and for surgically treated NEC patients was 40% (HR: 3.729; p < 0.001). At 2-year follow-up, one patient received parenteral nutrition. Severe delay in weight for age, motor, and cognitive development was seen in 3, 6, and 2%, respectively.

Conclusion In this cohort, the mortality rate was high, especially in surgically treated NEC patients. The surgical complication rate is comparable to previous studies, but in surviving patients, persisting IF and severe delay in growth and neurodevelopment at 2 years CA were relatively rare.
An interface trap charge model for simulation of graphene-based synaptic field effect transistors
Authors: Oshio Reon , Souma Satofumi
Published: January 2022

We propose a compact computational method based on the capacitance model for the efficient design of graphene-based synaptic field effect transistors (FETs), in which the hysteresis of conduction characteristics due to the channel–gate interface trap is used as synaptic plasticity. Using our method to calculate the conduction properties of graphene and armchair graphene nanoribbon (AGNR) superlattice FETs, it is shown that the AGNR can achieve an efficient conductance change rate Δw, which is approximately 7.4 times that of graphene. It was also found that Δw was the greatest when the gate oxide thickness was around 2–3 nm, which is near the limit of miniaturization. These results suggest that the proposed synaptic FETs are a promising approach to realize large scale integration chips for biological timescale computation.
Design of de Laval nozzles for gas-phase molecular studies in uniform supersonic flow
Authors: Durif O.
Published: January 2022

A method to design de Laval nozzles to generate uniform supersonic flows for gas-phase molecular studies at very low temperature is presented. The nozzle design is optimized for the flows in argon, helium, or nitrogen, up to Mach 5 and down to a few kelvin. Experimental results have shown that flows exhibit a good uniformity in terms of speed, temperature, and density, with the length of the uniformity of the supersonic flows up to 50 cm which corresponds to a kinetic time of about 1 ms in nitrogen for nozzles with a throat of about 1 cm in diameter. The design of the de Laval nozzles is concentrated at the diverging section. The method is based on the calculation of an isentropic core as described in Owen's work [J. M. Owen, “An improved method of supersonic nozzle design for rarefied gas flows,” Ph.D. thesis (University of California, 1950)] of supersonic nozzle design for rarefied gas flows. The determination of the isentropic nozzle wall is carried out by the method of characteristics following Cronvich's algorithm [L. Cronvich, “A numerical–graphical methods of characteristics for axially symmetric isentropic flow,” J. Aeronaut. Sci. 15, 156–162 (1948)]. The laminar boundary layer is corrected by employing Michel's integral method [R. Michel, “Aérodynamique: Couches limites, frottement et transfert de chaleur” (ENSAE, 1963)]. This approach has already largely shown its potency and had been widely used for 30 years in the field of experimental molecular physics or laboratory astrophysics [sometimes known under the french acronym CRESU for Cinetique de Réaction en Écoulement Supersonique Uniforme (reaction kinetics in uniform supersonic flow)]. Based on this approach, an in-house computer program with graphical user interface to design de Laval nozzles for kinetic studies is published for the first time.
Cylindrical metal liner implosion at extremes of pressure and material velocity on an intense pulsed power facility-FP-2
Authors: Sun Qizhi , Jia Yuesong , Zhang Zhengwei , Qin Weidong , Zhang Nanchuan , Zhou Rongguo , Liu Wei , Chi Yuan , Tian Qing , Wei Bing , Zhao Xiaoming , Liu Zhengfen
Published: January 2022

Highly precise and controllable liner implosions driven by a pulsed power facility have extensive applications in exploration of advanced hydrodynamics at the extremes of pressure and material velocity. In this paper, we describe a new pulsed power facility developed in China named FP-2 (a series of facilities for Fluid Physics investigations—the second generation) for liner implosions. Benefiting from the reliable and stable operation of 48 rail gap switches, the FP-2 facility can steadily transmit a current of 10.5 MA to a dummy load of 10 nH in the case of a charging voltage of ±40 kV. The first quarter cycle is 5.5 µs, and the percentage shot-to-shot deviation of the current history is less than 1%. When the aluminum liners of 60 mm in height and 0.6 mm in thickness are adopted, the maximum velocity of 4.5 and 7.5 km/s has been achieved with the liner diameter of 90 and 60 mm, respectively, at the diameter of 10 mm. Experimental results show that the percentage shot-to-shot deviation of the liner velocity history is less than 1%. As impact on the target, the maximum of the impact time deviation measured from four perpendicular fiber pins is less than 20 ns. Due to the modular design of FP-2, it is convenient for a future upgrade. The confirmation of high-quality implosion on FP-2, such as high repeatability, high reliability, and high symmetry, makes it a bright prospect to explore the advanced hydrodynamic problems at extremes of pressure and material velocity in the future.
Optical phonon limited electron mobility in ZnO nanowires wrapped by MgZnO shells
Authors: Xue Z. X. , Qu Y. , Ban S. L.
Published: January 2022

MgxZn1−xO shells are commonly used as a passivation barrier for improving electron mobility in ZnO nanowires by preventing electrons from charged surfaces. However, a high Mg mole fraction x instead makes lower electron mobility, which is usually attributed to the appearance of mixed-phase MgxZn1−xO as x increases. This work aims to find the optimal x for optical phonon limited electron mobility by considering the phase transformation in the MgZnO shell from wurtzite to rock salt, leading to a mixed-phase range of x. Our calculations show that the electron mobility μT can be effectively enhanced by keeping x below 0.057 when confined (CO1) optical phonons are only permitted for small wave vectors, and there is no interface (IF) optical phonon. Once x gets over 0.057, the propagating optical phonons are transformed into IF ones while CO1 phonons become permitted for all wave vectors resulting in a largely strengthened scattering effect and thus a drastic drop in the total electron mobility μT from 1215 to 310 cm2/V s. From then, μT begins to fall slowly as x increases even when the rock salt component in the shell appears to take the place of the wurtzite part, while the scattering from CO1 optical phonons remains primary. Furthermore, the enlarging core radius can weaken the electron–CO1 phonon interaction to enhance mobility.
Identifying nonadditive contributions to the hydrophobicity of chemically heterogeneous surfaces via dual-loop active learning
Authors: Kelkar Atharva S. , Dallin Bradley C. , Van Lehn Reid C.
Published: January 2022

Hydrophobic interactions drive numerous biological and synthetic processes. The materials used in these processes often possess chemically heterogeneous surfaces that are characterized by diverse chemical groups positioned in close proximity at the nanoscale; examples include functionalized nanomaterials and biomolecules, such as proteins and peptides. Nonadditive contributions to the hydrophobicity of such surfaces depend on the chemical identities and spatial patterns of polar and nonpolar groups in ways that remain poorly understood. Here, we develop a dual-loop active learning framework that combines a fast reduced-accuracy method (a convolutional neural network) with a slow higher-accuracy method (molecular dynamics simulations with enhanced sampling) to efficiently predict the hydration free energy, a thermodynamic descriptor of hydrophobicity, for nearly 200 000 chemically heterogeneous self-assembled monolayers (SAMs). Analysis of this dataset reveals that SAMs with distinct polar groups exhibit substantial variations in hydrophobicity as a function of their composition and patterning, but the clustering of nonpolar groups is a common signature of highly hydrophobic patterns. Further molecular dynamics analysis relates such clustering to the perturbation of interfacial water structure. These results provide new insight into the influence of chemical heterogeneity on hydrophobicity via quantitative analysis of a large set of surfaces, enabled by the active learning approach.
Probe of the excitonic transitions and lifetimes in quasi-2D organic–inorganic halide perovskites
Authors: Magill Brenden A. , Wang Kai , McGill Stephen , Stanton Christopher J. , Priya Shashank , Khodaparast Giti A.
Published: January 2022

Traditional organic–inorganic halide perovskites (OIHPs), in which perovskites layers are separated by an organic spacer material, have been mainly explored for photovoltaics devices, but they also offer promises for nonlinear optics and quantum light applications. These attributes include (a) high quantum efficiency, (b) large binding energy of excitons in low-dimensional structures, (c) polarons of long coherence times at room temperature, and (d) a large spin–orbit coupling. OIHP systems can be engineered to have photoluminescence (PL) emissions from UV to IR regions, in addition to power conversion efficiencies, in excess of 24%. This class of materials offers broad tunability of its properties, through controlling the number of atomic layers in the quantum well, tuning the organic spacer thickness, or even engineering the composition with exotic dopants. In this work, we present PL and time-resolved PL measurements of quasi-2D BA2PbI4 and provide new insights on the temperature dependence of their excitonic dynamics and fine structures of their PL emissions. We observed long lifetimes, which can result from the formation of large polarons, screening the Coulomb interactions of the charge carriers and reducing the scattering of the carriers with charge defects.
Ultra-high thermal stability of perpendicular magnetic anisotropy in the W buffered CoFeB/MgO stacks with Zr dusting layers
Authors: Guo Q. X. , Wang K. , Bai H. , Zheng Z. C. , Wang L. H. , Wang X. M. , He W. , Yu G. H. , Teng J. , Zhu T.
Published: January 2022

Practical device applications of magnetic multilayers with perpendicular magnetic anisotropy (PMA) usually need to match the mature complementary metal-oxide-semiconductor (CMOS) integrated techniques, which require high temperature annealing during the back-end-of-line process. Here, we report the realization of PMA in the W buffered CoFeB/MgO stack by inserting a thin Zr dusting layer between CoFeB and MgO layers. An ultra-high thermal stability of PMA in the W/CoFeB/Zr/MgO stack is observed, which is robust upon annealing at 600 °C. The establishment of PMA in W/CoFeB/Zr/MgO is due to the formation of an interface layer between CoFeB and MgO doped with oxidized Zr. After annealing at 540 °C, the magnetic interfacial anisotropy density reaches 3.08 erg/cm2, which is much higher than those in previous reports. The results suggest that the W/CoFeB/Zr/MgO stack with extra high annealing stability is a potential candidate to achieving the practical application of spin-logic device that is compatible with the mature CMOS integrated techniques.
Training and pattern recognition by an opto-magnetic neural network
Authors: Chakravarty A. , Mentink J. H. , Semin S. , Rasing Th.
Published: January 2022

Neuromorphic computing aims to mimic the architecture of the human brain to carry out computational tasks that are challenging and much more energy consuming for standard hardware. Despite progress in several fields of physics and engineering, the realization of artificial neural networks, which combine high operating speeds with fast and low-energy adaptability, remains a challenge. Here, we demonstrate an opto-magnetic neural network capable of learning and classification of digitized 3 × 3 characters exploiting local storage in the magnetic material. Using picosecond laser pulses, we find that micrometer sized synapses absorb well below 100 picojoule per synapse per laser pulse, with favorable scaling to smaller spatial dimensions. We, thus, managed to combine the speed and low-dissipation of optical networks with the low-energy adaptability and non-volatility of magnetism, providing a promising approach to fast and energy-efficient neuromorphic computing.
Wet-based digital etching on GaN and AlGaN
Authors: Shih Pao-Chuan , Engel Zachary , Ahmad Habib , Doolittle William Alan , Palacios Tomás
Published: January 2022

Many advanced III-nitride devices, such as micro-LEDs, vertical FinFETs, and field emitters, require the fabrication of high aspect ratio vertical pillars or nanowires. Two-step etchings combining dry and wet etching steps have been used on vertical devices in the past, but they show poor control in vertical nanostructures with sub-50 nm diameter. In this work, we demonstrate a wet-chemical digital etching on GaN and AlGaN and apply it to both vertical nanostructure scaling and planar etching along the c-axis. In this digital etching process, a mixture of H2SO4 and H2O2 is applied to oxidize the III-nitrides surface, and the oxide layer is then removed by dilute HCl. This digital etching approach can finely sharpen vertical structures and does not require any vacuum or plasma systems, which will enable advanced device structures in the future.
Giant tunneling magnetoresistance in atomically thin VSi2N4/MoSi2N4/VSi2N4 magnetic tunnel junction
Authors: Wu Qingyun , Ang Lay Kee
Published: January 2022

With rich electrical and magnetic properties and environmental stability, layered MSi2N4 (M = transition metal) has recently attracted much attention. By using a ferromagnetic VSi2N4 monolayer as an electrode and a semiconducting MoSi2N4 monolayer as a tunneling barrier, an atomically thin VSi2N4/MoSi2N4/VSi2N4 magnetic tunnel junction (MTJ) is theoretically proposed. Our calculated results suggest that the MTJ has a giant tunneling magnetoresistance (TMR) as large as 1010% and a near perfect (100%) spin injection efficiency (SIE). Our nonequilibrium Green's functions calculations indicate that the TMR and SIE are robust under a finite bias voltage of −100 mV to 100 mV. These results show that layered MSi2N4 can be promising materials for designing atomically thin MTJ with a giant TMR for future spintronic applications.
Capacitance–voltage characteristics of Pt/hBN/WSe2 metal–insulator–semiconductor capacitor doped by charge-transfer process
Authors: Im HoHyun , Lee Geonyeop , Park Hyunik , Lee Dongryul , Kim Jihyun
Published: January 2022

Metal–insulator–semiconductor (MIS) capacitors composed of low-dimensional van der Waals (vdW) materials are of fundamental interest for understanding carrier transport properties at the atomic scale. Herein, we fabricated a Pt/hBN/WSe2 MIS low-dimensional capacitor, followed by UV/ozone-induced oxidation to form a WOX layer, which is an electron-withdrawing agent. Capacitance–voltage (C–V) characteristics before and after p-doping of the WSe2 layer were compared for different durations of UV/ozone treatments. The C–V behaviors in the pristine condition exhibited ambipolar transport characteristics at both high and low frequencies because of co-existence of electron and hole carriers, which are advantageous for next-generation complementary MIS architectures. When WSe2 was p-doped, a typical p-type C–V curve with a high-frequency inversion region was observed, because the minority carriers (electrons) were unavailable. The frequency dispersions and ratios of the current to pristine hole concentrations as well as holes to electrons at different p-doping concentrations were analyzed. Finally, the controllability of the charge-transfer doping method was confirmed by chemically removing the WOX layer. The understanding of controllable and damage-free doping mechanisms in ambipolar vdW semiconductors is expected to help enhance electronic device performances at the atomic thickness.
Dual spin filtering and negative differential resistance effects in vanadium doped zigzag phosphorene nanoribbons with different edge passivations
Authors: Zhu H. H. , Liu N. , Feng Y. L. , Yao K. L. , Wang S. Y.
Published: January 2022

By applying density functional theory combined with nonequilibrium Green’s function, we investigate the electronic and transport properties of V-doped zigzag phosphorene nanoribbons (ZPNRs) with different edge passivations. The results show that the electronic and transport properties of vanadium-doped ZPNRs (V-ZPNRs) can be tuned by the edge passivation types. V-ZPNRs passivated by sulfur atoms possess stronger conductivity than bared ones, and edge passivation by hydrogen and halogen (F and Cl) atoms can transform V-ZPNRs from magnetic metals to magnetic semiconductors. Moreover, due to the edge passivation by hydrogen and halogen atoms, V-ZPNRs exhibit dual spin polarizability and negative differential resistance effects. The findings provide theoretical support in modulating the electronic transport properties of ZPNRs, which may be useful in designing phosphorene-based spintronic devices.
Fabrication of high-performance SnSe2 thermoelectric thin films with preferred crystallographic orientation
Authors: Heo Seung Hwae , Baek Seongheon , Shin Tae Joo , Son Jae Sung
Published: January 2022

SnSe2 has been of great interest as the n-type semiconductor exhibits high thermoelectric (TE) performance. Because material's thermoelectric properties are highly anisotropic, controlling the crystallographic orientation in the microstructure is one of the key factors for enhancing the TE performance. However, reports of SnSe2 with preferred crystallographic orientation have been limited due to the difficulty in fabrication. As a solution for this challenge, in this study, we report solution-processed fabrication of textured SnSe2 thin films. Following heat treatment optimization, the thin films possessed exceptionally strong crystallographic orientation order in the a–b plane, as demonstrated with x-ray diffraction analyses. Moreover, controlled defect formation through processing conditions realizes high electron concentrations of an order of ∼1020 cm−3. In particular, we demonstrate that the microstructure of the SnSe2 thin films determined their electronic transport properties, where the electron mobility increases with stronger crystallographic orientation. Finally, the thin film with the optimal structure exhibits the enhanced thermoelectric power factor of 3.69 μW cm−1 K−2. Our findings will offer a way to enhance the thermoelectric and electronic properties of highly anisotropic materials.
Discrete element simulations on the damaged surface hydrodynamics of tungsten powders with inert Ar gas
Authors: Pei Lei , Ma Zongqiang , Zhang Yang , Shi Xiaofeng , Ma Dongjun , Pan Hao , Wang Pei
Published: January 2022

Ejecta of micrometer-sized particles from a shocked damaged metal surface into a gas environment are widely observed in the engineering fields. Investigating the transport of ejecta particles in the converging geometries is a challenging scientific issue. Rousculp et al. [“Damaged surface hydrodynamics (DSH) flash report,” Report No. LA-UR-15-22889, 2015] have studied the transport of shock-launched tungsten powders from a cylindrical metal surface into an inert gas. In the so-called damaged surface hydrodynamic experiments, the effect of gas species on powder transport was investigated. Distinctive phenomena were observed in all cases in which particles aggregated into radial spikes or stripes with an azimuthal modulation of n > 20, though the initial powder coating was highly controlled and the shock loading was believed to be azimuthally uniform. In this work, discrete element method coupling with magneto-hydrodynamic simulations was employed to explore the mechanism behind the experimental phenomena. Results showed that stripes may be originated from the non-uniform initial distribution and small velocity difference of particles. The intense particle collision during the shock launching caused the microstripe-like structures, which merged into macroscopic ones observed in the subsequent particle transport process. Lagrange tracking revealed the stripes at different moments consisted of different particles. Oblique collisions played an important role in the long-term transport of ejecta particles in the convergence geometries, while the drag force of gas showed little influence. This work will promote the understanding of dense particle–gas flow in converging geometries.
Efficient beam manipulation with Huygens-geometric metasurface supporting pure magnetic resonances
Authors: Wang Xiaosai , Cui Ying , Liu Bingyi , Jiang Yongyuan
Published: January 2022

In this work, we propose the concept of Huygens-geometric metasurface by stimulating two magnetic dipoles with designated phases. A theoretical model is developed to reveal its physical mechanism, and the required conditions for zero-backward scattering are derived. We verify the model with an anisotropic all-dielectric meta-atom, which is composed of a thin silica layer sandwiched by two silicon nanofins. The meta-atom with a maximum conversion efficiency of 98.8% and robust against the variation of the structural parameters can be applied in high-efficiency transmitted beam manipulation, such as beam deflection and focusing. Our work paves the way for the development of high-performance functional meta-devices.
Rationalizing charge carrier transport in ternary organic solar cells
Authors: Hu Haixia , Mu Xinyu , Qin Wei , Gao Kun , Hao Xiaotao , Yin Hang
Published: January 2022

Ternary bulk heterojunction (BHJ) organic solar cells have energy offsets between multiple donors and acceptors. In such bi-continuous percolating films, electron carriers mainly transport in acceptor materials, and hole carriers typically transport in donor materials. Changing the third component of additional donors or acceptors is a common method to fine-tune the transport properties in ternary BHJs. Experimentally, although there are some empirical guidelines for the mobility evaluation, a clear charge transporting model has still not been fully established in multi-component BHJ films. Herein, we observed a general regularity about charge transport that the charge carriers have higher possibilities to transport in polymeric materials even if only low dosage (<10% in weight) polymeric materials are introduced for both the hole and electron cases. From the extended Su–Schrieffer–Heeger model, a polymer “bridge” assisted charge transport mode in small molecules is proposed after the energy offset exceeds the threshold (ΔEe > 0.15 eV). This work provides a perspective for fine tuning the charge transport property in high-performance ternary organic solar cells.
A multi-pulse wakeup scheme for on-chip operation of devices based on ferroelectric doped HfO2 thin films
Authors: Lancaster S. , Mikolajick T. , Slesazeck S.
Published: January 2022

A wakeup scheme for ferroelectric thin Hf0.5Zr0.5O2 films is presented, based on a gradual switching approach using multiple short pulses with a voltage amplitude roughly equal to the coercive voltage. This enables the on-chip wakeup and switching operation of ferroelectric devices, such as ferroelectric tunnel junctions (FTJs), with identical pulses. After wakeup using alternating pulse trains, which gradually switch the film polarization, FTJ operation is demonstrated to be as effective as after “normal” wakeup, with bipolar pulses of an amplitude larger than the coercive voltage. In this case, the voltage applied during wakeup was reduced by 26%, thereby lowering the required operating power.
Terahertz microscope with oblique subwavelength illumination: design principle
Authors: Minin O.V. , Minin I.V.
Published: January 2022

It is shown that the image contrast in the air when using a microscope based on dielectric microparticles with a size of the order of wavelength can be significantly enhanced with the help microparticles that provide the formation of the radiation localisation region at an angle to the direction of radiation incidence (at an angle to the optical axis). For this purpose, a screen is placed in front of the particle, which blocks part of the incident beam, forming a photonic hook or a photonic jet (terajet) with oblique illumination in the near field.
Age-related changes in the viscoelasticity of rabbit lens characterised by surface wave dispersion analysis
Authors: Zhang H. , Singh M. , Zvietcovich F. , Larin K. , Aglyamov S.
Published: January 2022

The viscoelastic properties of the young and mature rabbit lensesin situare evaluated using wave-based optical coherence elastography (OCE). Surface waves in the crystalline lens are generated using acoustic radiation force (ARF) focused inside the eyeball. Surface-wave dispersion is measured with a phase-stabilised optical coherence tomography (OCT) system. The Young’s modulus and shear viscosity coefficient are quantified based on a Scholte wave model. The results show that both elasticity and viscosity are significantly different between the young and mature lenses. The Young’s modulus of the lenses increased with age from 7.74 ± 1.56 kPa (young) to 15.15 ± 4.52 kPa (mature), and the shear viscosity coefficient increased from 0.55 ± 0.04 Pa s (young) and 0.86 ± 0.13 Pa s (mature). It is shown that the combination of ARF excitation, OCE imaging, and dispersion analysis enables nondestructive quantification of lenticular viscoelasticityin situand shows promise forin vivoapplications.
Theranostics of skin neoplasms based on luminescence diagnostics in combination with photodynamic therapy in the absorption band of porphyrin
Authors: Shilov I.P. , Gorshkova A.S. , Ivanov A.V. , Rumyantseva V.D. , Danielyan G.L. , Kashin V.V.
Published: January 2022

We report the results of developing a technique for theranostics of skin neoplasms based on luminescence diagnostics in combination with photodynamic therapy (PDT) in the absorption band of porphyrin. It is shown that the therapeutic effect is achieved exclusively due to PDT, without the participation of the hyperthermia process, which occurs at temperatures above 42°C. The Fluroscan gel [based on the dipotassium salt of the ytterbium complex of 2,4-di-(α-methoxyethyl)deuteroporphyrin IX (Yb-DMDP)] is used as a preparation for theranostics. The main photophysical properties and possible mechanisms of accumulation of nanosized low-toxic photosensitisers based on this compound are studied. It is shown that the Yb-DMDP compound in a DMSO solution (30 % aqueous DMSO) enhances photophysical characteristics (luminescence lifetime 5 – 10 μs, luminescence quantum yield up to 1 %, extinction coefficient ∼1.96 × 105 M−1 cm−1 at a wavelength of 398 nm). Experimental animals are used to test the proposed technique for theranostics of tumours using the Fluroscan gel and a fibre-optic laser fluorimeter.
Heterologous vaccination interventions to reduce pandemic morbidity and mortality: Modeling the US winter 2020 COVID-19 wave
Authors: Hupert Nathaniel , Marín-Hernández Daniela , Gao Bo , Águas Ricardo , Nixon Douglas F.
Published: January 2022

Significance

Control of the COVID-19 pandemic has been impeded by the slow global uptake of targeted vaccines, emergence of more transmissible variants, and resistance to continuation of nonpharmaceutical interventions. Commonly used vaccines can have nonspecific immune effects, and several have been shown to have beneficial heterologous effects against SARS-CoV-2 infection. However, there is no science-based guidance on effective implementation of such heterologous vaccine interventions (HVIs) to counter the current or future pandemics. We modeled the effect of different HVI strategies on the winter 2020 COVID-19 wave in the United States, finding that targeting both elderly and nonelderly populations and intervening during pandemic growth phases (i.e., effective reproduction number > 1) led to the greatest reduction in morbidity and mortality.
The ectomycorrhizal fungus
Pisolithus microcarpus
encodes a microRNA involved in cross-kingdom gene silencing during symbiosis
Authors: Wong-Bajracharya Johanna , Singan Vasanth R. , Monti Remo , Plett Krista L. , Ng Vivian , Grigoriev Igor V. , Martin Francis M. , Anderson Ian C. , Plett Jonathan M.
Published: January 2022

Significance

Plant genomes encode hundreds of genes controlling the detection, signaling pathways, and immune responses necessary to defend against pathogens. Pathogens, in turn, continually evolve to evade these defenses. Small RNAs, such as microRNAs (miRNAs), are one mechanism used by pathogens to overcome plant defenses and facilitate plant colonization. Mounting evidence would suggest that beneficial microbes, likewise, use miRNAs to facilitate symbiosis. Here, we demonstrate that the beneficial fungus
Pisolithus microcarpus
encodes a miRNA that enters plant cells and stabilizes the symbiotic interaction. These results demonstrate that beneficial fungi may regulate host gene expression through the use of miRNAs and sheds light on how beneficial microbes have evolved mechanisms to colonize plant tissues.
A genetic switch for male UV iridescence in an incipient species pair of sulphur butterflies
Authors: Ficarrotta Vincent , Hanly Joseph J. , Loh Ling S. , Francescutti Caroline M. , Ren Anna , Tunström Kalle , Wheat Christopher W. , Porter Adam H. , Counterman Brian A. , Martin Arnaud
Published: January 2022

Significance

Incipient species are at an intermediate stage of speciation where reproductive isolation is counteracted by the homogenizing effects of gene flow. Human activity sometimes leads such species to reunite, as seen in the Orange Sulphur butterfly, which forms large hybridizing populations with the Clouded Sulphur in alfalfa fields. Here we show that sex chromosomes maintain these species as distinct, while the rest of their genome is admixed. Sex chromosomes notably determine which males display to females a bright, iridescent UV signal on their wings. Genetic mapping, antibody stainings, and CRISPR knockouts collectively indicate that the gene
bric a brac
controls whether UV-iridescent nanostructures develop in each species, illustrating how a master switch gene modulates a male courtship signal.
Ship traffic connects Antarctica’s fragile coasts to worldwide ecosystems
Authors: McCarthy Arlie H. , Peck Lloyd S. , Aldridge David C.
Published: January 2022

Significance

Ship movements related to fishing, tourism, research, and supply expose the Antarctic continent to human impacts. Until now, only rough estimates or industry-specific information have been available to inform evidence-based policy to mitigate the introduction of nonnative marine species. Antarctica’s Southern Ocean supports a unique biota and represents the only global marine region without any known biological invasions. However, climate change is removing physiological barriers to potential invasive nonnative species and increasing ship activities are raising propagule pressure. The successful conservation of iconic Antarctic species and environments relies on addressing both climate change and direct, localized human impact. We have identified high-risk areas for introduced species and provide essential data that will underpin better evidence-based management in the region.
Multivalency enables unidirectional switch-like competition between intrinsically disordered proteins
Authors: Berlow Rebecca B. , Dyson H. Jane , Wright Peter E.
Published: January 2022

Significance

Intrinsically disordered proteins must frequently compete for binding to shared interaction hubs to perform their cellular functions. Here, we describe the mechanism by which two disordered proteins that regulate the transcriptional response to hypoxia compete for binding to the folded TAZ1 domain of the transcriptional coactivators CBP and p300. CITED2, a negative feedback regulator of HIF-1α, displaces HIF-1α from TAZ1 in a unidirectional, switch-like manner. Efficient competition for binding of the TAZ1 domain is highly dependent on the flexibility and multivalency of the HIF-1α and CITED2 activation domains. Differences in the strength of coupling of the CITED2 and HIF-1α binding motifs are key determinants of unidirectionality and underscore the role of multivalency in regulation of cellular processes by disordered proteins.