bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoscale thermal conductivity of Kapton-derived carbonaceous materials
Authors: Kondratenko K. , Hourlier D. , Vuillaume D. , Lenfant S.
Published: February 2022

This study exploits the nanoscale resolution of scanning thermal microscopy (SThM) to reveal inhomogeneous nature of thermal properties of carbon-derived materials issued from thermal conversion of the most commonly known polyimide, Kapton®. This information is otherwise inaccessible if conventional thermal characterization techniques are used due to their limited spatial resolution. Kapton films were pyrolyzed in an inert atmosphere to produce carbon-based residues with varying degree of conversion to free sp2 disordered carbon. The thermal conductivity of carbon materials ranges from 0.2 to 2 W m−1 K−1, depending on the temperature of the carbonization process (varied between 500 and 1200 °C). For quantitative measurements of thermal conductivity, the Null Point SThM (NP-SThM) technique is used in order to avoid unwanted effects as the parasitic heat flows through the air and the probe cantilever. It was found that NP SThM data for bulk materials are in excellent agreement with results obtained through more traditional techniques, namely, photo-thermal radiometry, flash laser analysis, and micro-Raman thermometry. This allowed us to use the NP-SThM technique to differentiate structural heterogeneities or imperfections at the surface of the pyrolyzed Kapton on the basis of the measured local thermal conductivity.
Ultrasensitive electrode-free and co-catalyst-free detection of nanomoles per hour hydrogen evolution for the discovery of new photocatalysts
Authors: Wang Huaiyu (Hugo) , Katzbaer Rowan R. , Fanghanel Julian , Schaak Raymond E. , Gopalan Venkatraman
Published: February 2022

High throughput theoretical methods are increasingly used to identify promising photocatalytic materials for hydrogen generation from water as a clean source of energy. While most promising water splitting candidates require co-catalyst loading and electrical biasing, computational costs to predict them a priori become large. It is, therefore, important to identify bare, bias-free semiconductor photocatalysts with small initial hydrogen production rates, often in the range of tens of nanomoles per hour, as these can become highly efficient with further co-catalyst loading and biasing. Here, we report a sensitive hydrogen detection system suitable for screening new photocatalysts. The hydrogen evolution rate of the prototypical rutile TiO2 loaded with 0.3 wt. % Pt is detected to be 78.0 ± 0.8 µmol/h/0.04 g, comparable with the rates reported in the literature. In contrast, sensitivity to an ultralow evolution rate of 11.4 ± 0.3 nmol/h/0.04 g is demonstrated for bare polycrystalline TiO2 without electrical bias. Two candidate photocatalysts, ZnFe2O4 (18.1 ± 0.2 nmol/h/0.04 g) and Ca2PbO4 (35.6 ± 0.5 nmol/h/0.04 g) without electrical bias or co-catalyst loading, are demonstrated to be potentially superior to bare TiO2. This work expands the techniques available for sensitive detection of photocatalytic processes toward much faster screening of new candidate photocatalytic materials in their bare state.
Do any types of double-hybrid models render the correct order of excited state energies in inverted singlet–triplet emitters?
Authors: Alipour Mojtaba , Izadkhast Tahereh
Published: February 2022

Organic emissive materials with the inverted singlet–triplet energy gaps, where in violation of Hund’s multiplicity rule the lowest triplet excited-state is higher in energy than the lowest singlet excited-state, have recently come into the limelight. This unique feature is of important relevance, where the emitters meeting the singlet–triplet inversion have potential to usher in the next generation of organic light emitting diodes (OLEDs). Since experimental data in this context are currently sparse, necessity of the cost-effective theoretical tools able to provide reliable results seems to be evident. Following our recent endeavors on the spin-component-scaled (SCS), spin-opposite-scaled (SOS), and SOS-range separated exchange (SOS-RSX) double-hybrids (DHs) as well as other efforts revealing the superior performances of such models for time-dependent computations, in the present work, we develop and validate several models based on the SOS-configuration interaction singles with perturbative doubles correction [SOS-CIS(D)] devoid of any fitting procedure for describing the singlet–triplet inversion. Taking a series of emitters with the available reference values for the inverted singlet–triplet energy gaps as working models, it is unveiled that the extremes of the same-spin and opposite-spin parameters included in the direct and indirect terms of the SOS-CIS(D) correlation energy as well as the nonlocal exchange and correlation contributions do not necessarily work well for the inverted gaps, but particular proportions among them are needed to achieve a reliable accuracy. Perusing the results of our developed methods, the best one based on the Perdew–Burke–Ernzerhof (PBE) exchange and correlation terms and the quadratic integrand model, denominated as SOS0-CIS(D)-PBE-QIDH, is shown to be highly efficient and robust for computations of the inverted singlet–triplet energy gaps. Furthermore, through detailed comparisons, we have also evaluated the performances of a variety of the recently presented DHs, including parameterized, parameter-free, RSX, as well as spin-component and spin-opposite scaling models for the purpose. Dissecting all the findings, it is disclosed that the results of any type of the DHs cannot be reliable, leading to positive energy gaps in most cases. Nonetheless, there are still some approximations, including SCS-PBE-QIDH, dispersion corrected spin-component scaled double-hybrids (DSD) of DSD-PBEP86 and DSD-BLYP, SOS-PBE-QIDH, SOS-ωPBEPP86, and SOS-RSX-QIDH, that can predict the negative singlet–triplet energy gaps for all the considered emitters and provide comparable performances with respect to our proposed model. To wrap up, among the large panel of different families of DHs on the market, the newly proposed model herein alongside these latter functionals can be recommended as the currently best affordable methods for subsequent applications on the inverted singlet–triplet emitters in OLED materials.
Impact of gigahertz and terahertz transport regimes on spin propagation and conversion in the antiferromagnet IrMn
Authors: Gueckstock O. , Seeger R. L. , Seifert T. S. , Auffret S. , Gambarelli S. , Kirchhof J. N. , Bolotin K. I. , Baltz V. , Kampfrath T. , Nádvorník L.
Published: February 2022

Control over spin transport in antiferromagnetic systems is essential for future spintronic applications with operational speeds extending to ultrafast time scales. Here, we study the transition from the gigahertz (GHz) to terahertz (THz) regime of spin transport and spin-to-charge current conversion (S2C) in the prototypical antiferromagnet IrMn by employing spin pumping and THz spectroscopy techniques. We reveal a factor of 4 shorter characteristic propagation lengths of the spin current at THz frequencies (∼0.5 nm) as compared to GHz experiments (∼2 nm). This observation may be attributed to different transport regimes. The conclusion is supported by extraction of sub-picosecond temporal dynamics of the THz spin current. We identify no relevant impact of the magnetic order parameter on S2C signals and no scalable magnonic transport in THz experiments. A significant role of the S2C originating from interfaces between IrMn and magnetic or non-magnetic metals is observed, which is much more pronounced in the THz regime and opens the door for optimization of the spin control at ultrafast time scales.
Topics on Fermi varieties of discrete periodic Schrödinger operators
Authors: Liu Wencai
Published: February 2022

This is a survey of recent progress on the irreducibility of Fermi varieties, rigidity results, and embedded eigenvalue problems of discrete periodic Schrödinger operators.
Spectroscopic signatures of plasmon-induced charge transfer in gold nanorods
Authors: Lee Stephen A. , Ostovar Behnaz , Landes Christy F. , Link Stephan
Published: February 2022

Plasmon-induced charge transfer has been studied for the development of plasmonic photodiodes and solar cells. There are two mechanisms by which a plasmonic nanoparticle can transfer charge to an adjacent material: indirect transfer following plasmon decay and direct transfer as a way of plasmon decay. Using single-particle dark-field scattering and photoluminescence imaging and spectroscopy of gold nanorods on various substrates, we identify linewidth broadening and photoluminescence quantum yield quenching as key spectroscopic signatures that are quantitatively related to plasmon-induced interfacial charge transfer. We find that dark-field scattering linewidth broadening is due to chemical interface damping through direct charge injection via plasmon decay. The photoluminescence quantum yield quenching reveals additional mechanistic insight into electron–hole recombination as well as plasmon generation and decay within the gold nanorods. Through these two spectroscopic signatures, we identify charge transfer mechanisms at TiO2 and indium doped tin oxide interfaces and uncover material parameters contributing to plasmon-induced charge transfer efficiency, such as barrier height and resonance energy.
A nearsighted force-training approach to systematically generate training data for the machine learning of large atomic structures
Authors: Zeng Cheng , Chen Xi , Peterson Andrew A.
Published: February 2022

A challenge of atomistic machine-learning (ML) methods is ensuring that the training data are suitable for the system being simulated, which is particularly challenging for systems with large numbers of atoms. Most atomistic ML approaches rely on the nearsightedness principle (“all chemistry is local”), using information about the position of an atom’s neighbors to predict a per-atom energy. In this work, we develop a framework that exploits the nearsighted nature of ML models to systematically produce an appropriate training set for large structures. We use a per-atom uncertainty estimate to identify the most uncertain atoms and extract chunks centered around these atoms. It is crucial that these small chunks are both large enough to satisfy the ML’s nearsighted principle (that is, filling the cutoff radius) and are large enough to be converged with respect to the electronic structure calculation. We present data indicating when the electronic structure calculations are converged with respect to the structure size, which fundamentally limits the accuracy of any nearsighted ML calculator. These new atomic chunks are calculated in electronic structures, and crucially, only a single force—that of the central atom—is added to the growing training set, preventing the noisy and irrelevant information from the piece’s boundary from interfering with ML training. The resulting ML potentials are robust, despite requiring single-point calculations on only small reference structures and never seeing large training structures. We demonstrated our approach via structure optimization of a 260-atom structure and extended the approach to clusters with up to 1415 atoms.
Spatiotemporal distributions of sweeping jet film cooling with a compact geometry
Authors: Zhou Wenwu , Wang Kechen , Yuan Tangjia , Wen Xin , Peng Di , Liu Yingzheng
Published: February 2022

The spatiotemporal distributions of the coolant coverage behind the 777-shaped hole, sweeping jet (SJ), and compact SJ were quantified comprehensively. Nitrogen gas was selected as the coolant, and its blowing ratio (M) was set from M = 1.0 to 3.0. The fast pressure-sensitive paint technique was applied to measure the instantaneous, mean, and unsteady film cooling effectiveness of the three configurations, and these data are compared side-by-side with the 777-shaped hole. The measured velocity spectra demonstrated a close level of Strouhal number for the SJ (St = 1.6–1.7) and compact SJ (St = 1.5–1.6). Due to the dynamic nature, both the SJ and compact SJ exhibited a highly unstable cooling effectiveness over the surface. Their effectiveness values were found to be lower than the 777 hole at relatively low M, but the compact SJ surpassed it and showed the highest effectiveness (i.e., the best cooling performance) as M ≥ 2.0 due to the widest coolant spreading. Compared with the SJ, the effectiveness of the compact SJ was consistently higher, but its coherence of flow structure was reduced, as revealed by a proper orthogonal decomposition analysis. Further simulations vividly describe the flow structures and oscillating processes inside the sweeping actuators. The SJ with compact geometry exhibited a lower exit momentum and more uniform coolant coverage than the SJ, leading to augmented adiabatic effectiveness.
Tuning of circular photogalvanic effect of surface states in the topological insulator Sb2Te3 via structural deformation
Authors: Wu Wenyi , Yu Jinling , Jiang Yuying , Zeng Xiaolin , Chen Yonghai , Liu Yu , Yin Chunming , Cheng Shuying , Lai Yunfeng , He Ke , Xue Qikun
Published: February 2022

Strain is a useful method to manipulate properties of three-dimensional (3D) topological insulators (TIs). In this study, we demonstrate the possibility to tune the circular photogalvanic effect (CPGE) of surface states of 3D TI Sb2Te3 films by applying external strain. The CPGE of 3D TI Sb2Te3 grown on SrTiO3 (STO) with different thicknesses has been systematically investigated. It is found that as the thickness of Sb2Te3 films increases from 7-quintuple layer (QL) to 27-QL, the CPGE current first increases and then decreases. Additionally, the CPGE currents demonstrate remarkable temperature dependence, which even reverse sign when the temperature is increased from 77 to 300 K. This phenomenon is due to the vertical thermoelectric effect and inverse spin Hall effect. Finally, the CPGE measurements of Sb2Te3 films under different mechanical strains are performed, and it is found that the CPGE current linearly decreases with the increase in the external strain. The variation in the CPGE current can be tuned up to 11% and 44% in the 18- and 12-QL Sb2Te3 grown on STO substrates under a tensile strain of 0.0225 and 0.0066, respectively. In particular, it can even reach 100% in the 30-QL Sb2Te3 film grown on an InP substrate under a tensile strain of 0.0033, which is due to the combined effect of mechanical deformation and spin injection from substrates. Our work provides a method to effectively manipulate the CPGE in 3D TIs by the combined effect of mechanical strain and spin injection from substrates, which paves the way for novel opto-spintronic devices.
On the topology patterns and symmetry breaking in two planar synthetic jets
Authors: Muñoz Eva , Le Clainche Soledad
Published: February 2022

This article studies the flow structures and main patterns driving the flow dynamics in one and two planar synthetic jets. We perform numerical simulations at different Reynolds numbers (Re), for a similar forcing frequency, to model the synthetic jet flow and the two planar synthetic jets, which present a movement in-phase (synchronous jets) and out-of-phase (asynchronous jets). We identify two types of flow regimes as function of the Reynolds number: (i) the flow is symmetric and (ii) the symmetry is broken at Re ≈110 and Re ≈140 for the single and the synchronous jets, respectively. On the contrary, the flow is always asymmetric in the two asynchronous jets. We calculate the thrust produced by the several jet configurations, finding that the thrust produced by a single jet is always half of the thrust produced by the two synchronous jets; however, this quantity is much smaller in the asynchronous jets. Finally, we use higher order dynamic mode decomposition to identify the main patterns driving the flow dynamics. The solution is periodic in the single and two synchronous jets, with the forcing frequency (St*) as the dominant mode. The emerging rise in amplitude of a low-frequency mode (St0 = St*/6) that sub-harmonic of the forcing frequency as the Reynolds number increases suggests a connection between this mode and the symmetry breaking. A new mode is identified in the asynchronous jets, breaking the flow periodicity.
Comparing the shock sensitivity of insensitive energetic materials
Authors: Akhtar Meysam , Dlott Dana D.
Published: February 2022

We present a tabletop method to study the shock sensitivity of plastic-bonded explosives that are considered shock insensitive using high dynamic range optical emission spectroscopy with laser-launched km/s flyer plate impacts (2, 3, and 4 km/s), which measures the spectral radiance (the emission spectrum vs a calibrated intensity standard) every 0.8 ns in the nanosecond and microsecond regimes. The explosives were TATB (1,3,5 trinitro, 2,4,6 triamino benzene), FOX-7 (1,1-diamino-2,2-dinitroethylene), LLM-105 (2,6-diamino-3,5-dinitropyrazine-1-oxide), and NTO (nitrotriazolone), all with 20% Sylgard 182 binder. Time resolving emission from shocked explosives produces a unique fingerprint at each shock pressure, and the emission temporal profile can be used to understand each material's shock response and the underlying mechanisms within the framework of the well-known shock ignition and growth models. Ignition was characterized by the emission intensity during nanosecond hot spot ignition. The growth process, which occurs after the shock has unloaded, was characterized by the time derivative of microsecond emission intensity. Singular-value decomposition was used to determine a characteristic spectral radiance over the entire time range, and this radiance was fit to a graybody model to determine a characteristic temperature Tc. Even though these insensitive explosives have similar shock sensitivities, our method can clearly distinguish their shock response. FOX-7 and NTO were the most sensitive, with FOX-7 having the greatest shock ignition sensitivity, growth rate, and Tc. LLM-105 was much less sensitive than FOX-7 and NTO, and TATB consistently showed the lowest sensitivity by any measure.
Toward accurate ab initio modeling of siliceous zeolite structures
Authors: Trachta Michal , Rubeš Miroslav , Bludský Ota
Published: February 2022

Structures of purely siliceous materials in the International Zeolite Association database were investigated with four different theoretical methods ranging from the empirical approaches, such as the distance least squares and force fields to the computationally demanding dispersion-corrected density functional theory method employing the generalized gradient approximation-type functional. The structural characteristics were first evaluated for dense silica polymorphs, for which reliable low-temperature experiments are available. Due to the significant errors in experimentally determined atomic positions of siliceous zeolites, lattice parameters and the cell volume were proposed as reliable descriptors for the structural assessment of zeolite frameworks. In this regard, the most consistently performing (systematically underestimating/overestimating) methods are the Sanders–Leslie–Catlow (SLC) force field and the PBEsol density functional. The best overall agreement with the experiment is observed for PBEsol-D2. However, it is a result of fortuitous error cancellations rather than improved description upon adding dispersion correction. We proposed two approaches to estimate accurate cell volumes of siliceous materials from theoretical data: (i) using the SLC and PBEsol volumes as lower and upper bounds and (ii) using a structural response to the dispersion correction along with the SLC compressibility as an additional criterion.
Excess noise in high-current diamond diodes
Authors: Ghosh Subhajit , Surdi Harshad , Kargar Fariborz , Koeck Franz A. , Rumyantsev Sergey , Goodnick Stephen , Nemanich Robert J. , Balandin Alexander A.
Published: February 2022

We report the results of an investigation of low-frequency excess noise in high-current diamond diodes. It was found that the electronic excess noise of the diamond diodes is dominated by the 1/f and generation-recombination noise, which reveals itself as Lorentzian spectral features (f is the frequency). The generation-recombination bulges are characteristic of diamond diodes with lower turn-on voltages. The noise spectral density dependence on forward current, I, reveals three distinctive regions in all examined devices—it scales as I2 at the low (I < 10 μA) and high (I > 10 mA) currents and, rather unusually, remains nearly constant at the intermediate current range. The characteristic trap time constants, extracted from the noise data, show a uniquely strong dependence on current. Interestingly, the performance of the diamond diodes improves with the increasing temperature. The obtained results are important for the development of noise spectroscopy-based approaches for device reliability assessment for high-power diamond electronics.
Stomatal size and density trade-off varies with leaf phenology and species shade tolerance in a South Asian moist tropical forest
Authors: Rahman Abdullah Al-Nur Shanto , Rahman Mizanur , Shimanto Mehedi Hasan , Kibria Mohammad Golam , Islam Mahmuda
Published: February 2022

The density and guard cell length of stomata regulate the physiological processes in plants. Yet, the variation of stomatal characteristics among different functional groups of trees is not been well understood. Particularly, a comprehensive understanding of stomatal behaviour in Bangladeshi moist forest trees is lacking. The study investigated how abaxial stomatal density (SD) and guard cell length (GCL) vary among tree functional types and leaf phenological groups in a moist tropical forest of Bangladesh. Cluster dendrogram revealed three groups of species based on SD and GCL. The independent sample t-test showed that there was a significant difference in SD between evergreen and deciduous tree species (t = 4.18, P < 0.001) but no significant difference in GCL between the two phenological groups. ANOVA revealed no significant difference in SD among the light demanding, intermediate shade tolerant and shade tolerant species (F = 0.76, P = 0.47). However, GCL significantly differed among the three functional groups (F = 3.3, P < 0.05). Maximum theoretical stomatal conductance (gmax) varied between evergreen and deciduous species but did not vary with species shade tolerance. In general, there was a significant trade-off between SD and GCL. However, the inverse relationship was stronger in deciduous and shade tolerant species than in evergreen and shade intolerant species. Leaf dry matter content was positively related with SD and negatively related with GCL. Specific leaf area and leaf thickness were not related to the stomatal traits. Our analyses suggest that leaf phenology and species shade tolerance need to be considered while estimating gas exchange through the stomata in tropical moist forests.
Effectiveness of health literacy- and patient activation-targeted interventions on chronic disease self-management outcomes in outpatient settings: a systematic review
Authors: Hosseinzadeh H. , Downie S. , Shnaigat M.
Published: February 2022

Chronic diseases are the leading causes of morbidity and mortality and account for approximately 60% of all deaths worldwide. Self-management is a key strategy to manage chronic diseases, and there is emerging evidence recommending targeting both health literacy (HL) and patient activation (PA) to improve chronic disease self-management outcomes. The aim of this systematic review is to summarise the current evidence on the impact of HL- and PA-led interventions on self-management outcomes using randomised control trials (RCTs). Six well known databases (MEDLINE, Web of Science, Scopus, Science Citation Index, EMBASE and Academic Search Complete) were searched for RCTs of chronic disease self-management interventions targeting both HL and PA and published between 2004 and June 2021. The search terms included chronic disease, self-management, patient activation/engagement and health literacy/education. Ten studies were eligible for inclusion. We found that patients with low HL and PA levels are most likely to benefit from the interventions. The moderate improvements in PA and HL in the reviewed studies were translated into some improvements in physical activity and mental health outcomes but failed to improve patients’ quality of life and healthcare utilisation outcomes. Patients with low HL were more likely to have higher PA levels after the interventions. This review suggests that both HL and PA are essential pillars for improving chronic disease self-management outcomes. However, more studies are needed to explore the long-term impacts of a combination of HL and PA on chronic disease self-management outcomes.
Pericyte dysfunction and loss of interpericyte tunneling nanotubes promote neurovascular deficits in glaucoma
Authors: Alarcon-Martinez Luis , Shiga Yukihiro , Villafranca-Baughman Deborah , Belforte Nicolas , Quintero Heberto , Dotigny Florence , Cueva Vargas Jorge L. , Di Polo Adriana
Published: February 2022

Significance

The current lack of understanding of the mechanisms leading to neurovascular deficits in glaucoma is a major knowledge gap in the field. Retinal pericytes regulate microcirculatory blood flow and coordinate neurovascular coupling through interpericyte tunneling nanotubes (IP-TNTs). We demonstrate that pericytes constrict capillaries in a calcium-dependent manner during glaucomatous stress, decreasing blood supply and compromising neuronal function. Moreover, ocular hypertension damages IP-TNTs and impairs light-evoked neurovascular responses. The reestablishment of calcium homeostasis in pericytes restores vascular and neuronal function, and prevents retinal ganglion cell death in glaucomatous eyes. This study provides important insights into the therapeutic potential of pericytes to counter vascular dysregulation in glaucoma.
CCR8-targeted specific depletion of clonally expanded Treg cells in tumor tissues evokes potent tumor immunity with long-lasting memory
Authors: Kidani Yujiro , Nogami Wataru , Yasumizu Yoshiaki , Kawashima Atsunari , Tanaka Atsushi , Sonoda Yudai , Tona Yumi , Nashiki Kunitaka , Matsumoto Reimi , Hagiwara Masaki , Osaki Motonao , Dohi Keiji , Kanazawa Takayuki , Ueyama Azumi , Yoshikawa Mai , Yoshida Tetsuya , Matsumoto Mitsunobu , Hojo Kanji , Shinonome Satomi , Yoshida Hiroshi , Hirata Michinari , Haruna Miya , Nakamura Yamami , Motooka Daisuke , Okuzaki Daisuke , Sugiyama Yasuko , Kinoshita Makoto , Okuno Tatsusada , Kato Taigo , Hatano Koji , Uemura Motohide , Imamura Ryoichi , Yokoi Kazunori , Tanemura Atsushi , Shintani Yasushi , Kimura Tadashi , Nonomura Norio , Wada Hisashi , Mori Masaki , Doki Yuichiro , Ohkura Naganari , Sakaguchi Shimon
Published: February 2022

Significance

Immunosuppressive Foxp3-expressing regulatory T cells (Tregs) in tumor tissues are assumed to be clonally expanding via recognizing tumor-associated antigens. By single-cell RNA sequencing, we have searched for the molecules that are specifically expressed by such multiclonal tumor Tregs, but not by tumor-infiltrating effector T cells or natural Tregs in other tissues. The search revealed the chemokine receptor CCR8 as a candidate. Treatment of tumor-bearing mice with cell-depleting anti-CCR8 antibody indeed selectively removed multiclonal tumor Tregs without affecting effector T cells or tissue Tregs, eradicating established tumors with induction of potent tumor-specific effector/memory T cells and without activating autoimmune T cells. Thus, specific depletion of clonally expanding tumor Tregs is clinically instrumental for evoking effective tumor immunity without autoimmune adverse effects.
Steering CO
2
hydrogenation toward C–C coupling to hydrocarbons using porous organic polymer/metal interfaces
Authors: Zhou Chengshuang , Asundi Arun S. , Goodman Emmett D. , Hong Jiyun , Werghi Baraa , Hoffman Adam S. , Nathan Sindhu S. , Bent Stacey F. , Bare Simon R. , Cargnello Matteo
Published: February 2022

Significance

In the field of CO
2
conversion, a crucial reaction for a sustainable future, controlling the selectivity to improve C–C coupling to higher products is challenging because of the notorious inertness of CO
2
and the stepwise conversion that occurs on conventional catalysts. Here, we show that porous polymer encapsulation of metal-supported catalysts is capable of driving the selectivity in the CO
2
conversion to hydrocarbons. With this strategy, we achieve an outstanding improvement in C–C coupling that results in orders of magnitude higher turnover frequencies for hydrocarbon formation compared to conventional catalysts.
Nonenzymatic assembly of active chimeric ribozymes from aminoacylated RNA oligonucleotides
Authors: Radakovic Aleksandar , DasGupta Saurja , Wright Tom H. , Aitken Harry R. M. , Szostak Jack W.
Published: February 2022

Significance

The emergence of a primordial ribosome from the RNA world would have required access to aminoacylated RNA substrates. The spontaneous generation of such substrates without enzymes is inefficient, and it remains unclear how they could be selected for in a prebiotic milieu. In our study, we identify a possible role for aminoacylated RNA in ribozyme assembly, a longstanding problem in the origin-of-life research. We show that aminoacylation of short RNAs greatly accelerates their assembly into functional ribozymes by forming amino acid bridges in the phosphodiester backbone. Our work therefore addresses two key challenges within the origin-of-life field: we demonstrate assembly of functional ribozymes, and we identify a potential evolutionary benefit for RNA aminoacylation that is independent of coded peptide translation.
Extracción de fraseología especializada basada en corpus
Authors: Gallego-Hernández Daniel
Published: February 2022

Abstracta

En este trabajo se describe la evaluación de extracción de unidades fraseológicas especializadas a partir de un corpus español. Tras repasar brevemente diversos estudios en torno a los conceptos de unidad terminológica y unidad fraseológica especializada, así como su identificación y extracción, se presenta un protocolo de evaluación centrado en aspectos de usabilidad y precisión que se aplica a tres sistemas de explotación de corpus. Los resultados confirman parcialmente la hipótesis de que los extractores terminológicos permiten extraer unidades fraseológicas especializadas. Por último, se hacen algunas sugerencias con el ánimo de optimizar el funcionamiento de estos sistemas.
Voice evaluation – contribution of the speech-language pathologist voice specialist – SLP-V
Authors: Behlau Mara , Madazio Glaucya , Vaiano Thays , Pacheco Claudia , Badaró Flávia
Published: February 2022

The human voice is the product of a sophisticated interaction of aerodynamic and myoelastic forces, a perceptual phenomenon that is greatly influenced by vocal behaviour in interpersonal relationships. Vocal problems can be overly complex and can require a team approach, whether for diagnosis or treatment of the patient. This article describes the contribution of the speech-language pathologist, voice specialist SLP-V in the assessment of patients with vocal complaints. A clinical evaluation proposal developed in a 40- to 60-min session is presented. This proposal consists of the following steps: the history of the problem; the patient self-assessment; the auditory perceptual judgement and acoustic analysis; the physical examination; and finally, the correlation of all previously described steps with the medical diagnosis. Part A of this text explores the history of the problem with the focus to determine the influence of the vocal behaviour on the case; the self-assessment of the impact of the voice problem to verify the patient experience in living and coping with dysphonia; and the auditory perceptual judgement to describe the type and degree of vocal deviation. Worldwide published tendencies and specific comments of each step highlight the role of the SLP-V.
Real-time identification of PMSM losses through a novel past-time averaging method
Authors: Zeaiter Amal , Videcoq Etienne , Fénot Matthieu
Published: February 2022

The aim of this paper is the identification of unknown losses in a permanent-magnet synchronous motor through the thermal assessment of the motor behavior. These unknown losses can be sometimes hardly determined with analytical calculations. Their influence could be critical to some materials of the electric motor, such as windings and rotor, which are sensitive to hot-spot temperatures. The evaluation of the evolution of these unknown losses during cycles of mission is a crucial step in the motor conception phase. The applied method consists in solving a heat transfer inverse problem in real time. A new approach is used in this study for the regularization of the solution. It is based on a past-time averaging method. The work is numerically carried out based on a lumped-parameter thermal model developed for a high specific-power motor for the propulsion of hybrid aircrafts. Few reachable temperature nodes with known data are considered for the simulation. A dynamical mission profile is studied herein for a flight scenario of a hybrid aircraft, propelled by motors having around 1 MW of power. Three cases are investigated for the losses identification using the inverse technique. A study on the number of past time steps for the regularization of the ill-posed problem is presented. The results show that the thermal heat dissipated due to losses can be accurately estimated with an acceptable average error. The proposed procedure allows real-time determination of losses and monitoring of critical temperatures.
A review on ferroelectric systems for next generation photovoltaic applications
Authors: Pal Subhajit , Sarath N V , Priya K Shanmuga , Murugavel P
Published: February 2022

Ferroelectric (FE) materials, which are non-centrosymmetric crystal systems with switchable polarization characterization, are known to show multifunctional application potential in various fields. Among them, the FE photovoltaic (PV) phenomenon, which has been known for several decades, is finding renewed interest recently due to its anomalous PV characteristics along with the reported efficiency exceeding the Shockley–Queisser limit in the nanoscale region. Importantly, the mechanism involved in the FE–PV effect is particularly different from the conventional PV effect exhibited by the semiconductor p–n junction solar cell. The observed above bandgap photovoltage in the FE system, and the versatility in their tunable physical characteristics makes them as one of the next generation PV materials both in terms of fundamental and technological research. However, the biggest barrier in developing the FE–PV solar cells is their very low photocurrent response, which could be surmounted by bandgap engineering, surface charge manipulation, interface control, electrode effect etc. Interestingly, the PV response coupled with other physical phenomena such as piezoelectric and flexoelectric effect gives additional momentum to the continuing research on FE–PV effect. In this article, the detailed understanding associated with various proposed mechanisms, recent progress on the improvement in FE–PV parameters, PV phenomenon coupling with other fascinating effects exhibited by FE systems are described from the fundamental to application point of view.
Fowler-Nordheim tunneling in β-Ga2O3/SrRuO3 Schottky interfaces
Authors: Li Jiahao , Ji Yanda , Pan Rui , Zhao Run , Yuan Ye , Li Weiwei , Yang Hao
Published: February 2022

Interfaces in heterostructures always emerge as prototype electronic devices with tunable functionality. The fundamental properties of these interfaces can be finely manipulated by epitaxy engineering. Recently, heterostructures based on Ga2O3, an ultra-wide bandgap semiconductor, have been reported for use in high powered device applications. Herein, we will demonstrate a heterostructure of β-Ga2O3/SrRuO3 integrated on c-plane sapphire, where the high density of edge dislocations are evidenced in the heterostructure interfaces. Apart from the dominant Schottky emission mechanism, Fowler-Nordheim tunneling is also revealed by leakage current analysis, which may be ascribed to the edge dislocations at the interfaces. These results boost the basic understanding of ultra-wide bandgap materials and devices.
New insight into degradation of chloramphenicol using a nanoporous Pd/Co3O4 cathode: characterization and pathways analysis
Authors: Chen Yiwen , He Junguo , Jiang Peigen , Pang Heliang , Hu Xuhui , Zhang Jie , Zhang Wenjing
Published: February 2022

The growing chloramphenicol (CAP) in wastewater brought a serious threat to the activity of activated sludge and the spread of antibiotics resistance bacteria. In this study, a highly ordered nanoporous Co3O4 layer on Co foil through anodization was prepared as cathode for nitro-group reduction and electrodeposited with Pd particles for dechlorination to reduce CAP completely. After 3 h treatment, almost 100% of CAP was reduced. Co2+ ions in Co3O4 served as catalytic sites for electrons transfer to CAP through a redox circle Co2+–Co3+–Co2+, which triggered nitro-group reduction at first. With the presence of Pd particles, more atomic H* were generated for dechlorination, which increased 22% of reduction efficiency after 3 h treatment. Therefore, a better capacity was achieved by Pd/Co3O4 cathode (K = 0.0245 min−1, K is reaction constant) than by other cathodes such as Fe/Co3O4 (K = 0.0182 min−1), Cu/Co3O4 (K = 0.0164 min−1), and pure Co3O4 (K = 0.0106 min−1). From the proposed reaction pathway, the ultimate product was carbonyl-reduced AM (dechlorinated aromatic amine product of CAP) without antibacterial activity, which demonstrated this cathodic technology was a feasible way for wastewater pre-treatment.
Perspectives of measuring gravitational effects of laser light and particle beams
Authors: Spengler Felix , Rätzel Dennis , Braun Daniel
Published: February 2022

We study possibilities of creation and detection of oscillating gravitational fields from lab-scale high energy, relativistic sources. The sources considered are high energy laser beams in an optical cavity and the ultra-relativistic proton bunches circulating in the beam of the large hadron collider (LHC) at CERN. These sources allow for signal frequencies much higher and far narrower in bandwidth than what most celestial sources produce. In addition, by modulating the beams, one can adjust the source frequency over a very broad range, from Hz to GHz. The gravitational field of these sources and responses of a variety of detectors are analyzed. We optimize a mechanical oscillator such as a pendulum or torsion balance as detector and find parameter regimes such that—combined with the planned high-luminosity upgrade of the LHC as a source—a signal-to-noise ratio substantially larger than 1 should be achievable at least in principle, neglecting all sources of technical noise. This opens new perspectives of studying general relativistic effects and possibly quantum-gravitational effects with ultra-relativistic, well-controlled terrestrial sources.
Collective response of microrobotic swarms to external threats
Authors: Chen Chun-Jen , Bechinger Clemens
Published: February 2022

Many animal species organize within groups to achieve advantages compared to being isolated. Such advantages can be found e.g. in collective responses which are less prone to individual failures or noise and thus provide better group performance. Inspired by social animals, here we demonstrate with a swarm of microrobots made from programmable active colloidal particles (APs) that their escape from a hazardous area can originate from a cooperative group formation. As a consequence, the escape efficiency remains almost unchanged even when half of the APs are not responding to the threat. Our results not only confirm that incomplete or missing individual information in robotic swarms can be compensated by other group members but also suggest strategies to increase the responsiveness and fault-tolerance of robotic swarms when performing tasks in complex environments.
Nonlinear compact localized modes in flux-dressed octagonal-diamond lattice
Authors: Stojanović M G , Gündoğdu S , Leykam D , Angelakis D G , Stojanović Krasić M , Stepić M , Maluckov A
Published: February 2022

Tuning the values of artificial flux in the two-dimensional octagonal-diamond lattice drives topological phase transitions, including between singular and non-singular flatbands. We study the dynamical properties of nonlinear compact localized modes that can be continued from linear flatband modes. We show how the stability of the compact localized modes can be tuned by the nonlinearity strength or the applied artificial flux. Our model can be realized using ring resonator lattices or nonlinear waveguide arrays.
Adding Automation and Independent Dual Verification to Reduce Wrong Blood in Tube (WBIT) Events
Authors: Passwater Michael , Huggins Y Monique , Delvo Favre Elaine D , Mukhtar Faisal , Pelletier J Peter R
Published: February 2022

Objectives

Transfusions remain a complicated procedure involving many disciplines performing various steps. Pretransfusion specimen identification errors remain a concern. Over the past two decades, system changes have been made and minimal improvements in the error rates have been seen. Wrong blood in tube (WBIT) events may lead to mistransfusions of components with life-threatening complications.

Methods

A continuous quality improvement effort involving the introduction of electronic patient identification at the point of pretransfusion specimen collection (an automated system improvement), manual independent dual verification, and periodic education (human process system improvements) were implemented.

Results

Both automated and human system process improvements resulted in greater than 10-fold reduction in WBIT events and a 47% reduction in mislabeled specimens.

Conclusions

Diligent improvement and implementation of combination automated system processes and human protocols with continuous monitoring led to great reductions in WBIT error rates and labeling discrepancies, leading to an increase in system safety. These combinations of improvement can lead to more decreased error rates if applied to other critical process steps in the transfusion process.
Role of Histidine 78 of leaf ferredoxin in the interaction with ferredoxin-NADP+ reductase: regulation of pH dependency and negative cooperativity with NADP(H)
Authors: Kimata-Ariga Yoko , Fukuta Karen , Miyata Masayuki
Published: February 2022

In chloroplast stroma, dynamic pH change occurs in response to fluctuating light conditions. We investigated the pH-dependent electron transfer activity between ferredoxin-NADP+ reductase (FNR) and ferredoxin (Fd) isoproteins from maize leaves. By increasing pH (from 5.5 to 8.5), the electron transfer activity from FNR to photosynthetic-type Fd (Fd1) significantly increased while the activity to nonphotosynthetic type Fd (Fd3) decreased, which was mainly due to their differences in the pH dependency of Km for Fd. Mutation of His78 of Fd1 to Val, corresponding amino acid residue in Fd3, lost the pH dependency, indicating a regulatory role of the His78 in the interaction with FNR. We previously showed that the interaction between FNR and Fd was weakened by the allosteric binding of NADP(H) on FNR. His78Val Fd1 mutant largely suppressed this negative cooperativity. These results indicate the involvement of Fd1 His78 in pH dependency and negative cooperativity in the interaction with FNR.
The Empowerment of Informal Female Workers: A Case Study for Social Work Intervention in Tehran Province
Authors: Jaafari Fatemeh , Barrera-Algarín Evaristo , Webb Stephen A , Aryaee Sara
Published: February 2022

Informal employment constituting a major part of Iranian economy correlates strongly with social deprivation. The aim of the present study is to understand the mechanisms that lead to deprivation and how formalisation can empower informal workers. The study is of qualitative type using grounded theory and thematic analysis. The participants were thirty-two female workers and twelve elites selected through stratified sampling. In-depth interviews were used to collect data. Data were analysed through theoretical coding. The findings indicate that informal occupation is considered as a survival mechanism for women with deficient capital (deficient psychological, social, economic and legal capitals). In other words, women enjoying less power in legal, economic, social and psychological areas enter this domain, stay therein or exit. Based on the findings, informal occupation is a five-stage process where the female workers can be placed according to their status. The phases include pre-awareness, awareness, action, regression and emancipation. Moreover, using the model of formalising social work through empowerment and its tetrad (psychological, social, economic and legal empowerments), the formalising social worker can facilitate the formalisation of workers and their progress towards the emancipation stage, so that the workers could gain more access to the minimum and lowest social protection.
DNAJC30 defect: a frequent cause of recessive Leber hereditary optic neuropathy and Leigh syndrome
Authors: Stenton Sarah L. , Tesarova Marketa , Sheremet Natalia L. , Catarino Claudia B. , Carelli Valerio , Ciara Elżbieta , Curry Kathryn , Engvall Martin , Fleming Leah R. , Freisinger Peter , Iwanicka-Pronicka Katarzyna , Jurkiewicz Elżbieta , Klopstock Thomas , Koenig Mary K. , Kolářová Hana , Kousal Bohdan , Krylova Tatiana , La Morgia Chiara , Nosková Lenka , Piekutowska-Abramczuk Dorota , Russo Sam N. , Stránecký Viktor , Tóthová Iveta , Träisk Frank , Prokisch Holger
Published: February 2022

The recent description of biallelic DNAJC30 variants in Leber hereditary optic neuropathy (LHON) and Leigh syndrome challenged the longstanding assumption for LHON to be exclusively maternally inherited and broadened the genetic spectrum of Leigh syndrome, the most frequent paediatric mitochondrial disease. Herein, we characterize 28 so far unreported individuals from 26 families carrying a homozygous DNAJC30 p.Tyr51Cys founder variant, 24 manifesting with LHON, two manifesting with Leigh syndrome, and two remaining asymptomatic. This collection of unreported variant carriers confirms sex-dependent incomplete penetrance of the homozygous variant given a significant male predominance of disease and the report of asymptomatic homozygous variant carriers. The autosomal recessive LHON patients demonstrate an earlier age of disease onset and a higher rate of idebenone-treated and spontaneous recovery of vision in comparison to reported figures for maternally inherited disease. Moreover, the report of two additional patients with childhood- or adult-onset Leigh syndrome further evidences the association of DNAJC30 with Leigh syndrome, previously only reported in a single childhood-onset case.