bluuebunny/crossref_metadata_2025 huggingface dataset:
Stacking efficiency of terrestrial Plant-Microbial Fuel Cells growing Ocimum basilicum and Origanum vulgare
Authors: Pamintuan Kristopher Ray S. , Ancheta Arnie Jantzen G. , Robles Shaina Marie T.
Published: July 2020

Plant-Microbial Fuel Cells (PMFCs) are an emerging type of renewable energy that generates an electric current through the consumption of rhizodeposits by exoelectrogenic bacteria that lives in the rhizosphere of the plant. Since the plant is not harmed by the energy-harvesting process, PMFC technology has the potential to simultaneously produce food (biomass) and generate electricity. As of now, power densities of PMFCs have remained low and commercialization is not yet possible. To achieve higher power densities, the stacking behaviour of PMFCs needs to be studied. In this study, several cells growing Ocimum basilicum (basil) and Origanum vulgare (oregano) were constructed and evaluated. Upon stacking, it was shown that the constructed PMFCs did indeed behave like batteries, where the voltage of cells connected in series are additive, and that the voltage of cells connected in parallel are constant. The actual values of voltage of stacked cells are similar to the expected value (α=0.05). Cumulative stacking tests revealed that there is no apparent loss in voltage upon stacking up to 9 cells growing O. basilicum. Further computation of power and power densities have proven that stacking is a viable method of amplifying electricity generation in PMFCs, as both increased with increasing number of cells connected in series.
Effect of co-digestion of food waste and cow dung on biogas yield
Authors: Emmanuel Pax Makhura , Muzenda Edison , Lekgoba Tumeletso
Published: July 2020

This paper aims at finding the effect of co-digestion of cow dung and food waste on total biogas yield. Biogas production was improved through co-digestion of cow dung and food waste (FW) containing a small fraction of inoculum under mesophilic temperature (37ºC) over a retention time of 24 days. Co-digestion ratios of 1:1, 2:1 and 3:1 for cowdung/foodwaste were used for the study on anaerobic digestion on the co digested matter. Tests were carried out starting with the preparation of substrates, substrate characterization to determine the moisture content (MC), total solids (TS), volatile solids (VS) and ultimately batch anaerobic digestion experiments under thermophilic conditions (370C). The moisture content, volatile solids and total solids for food waste were 78, 22 and 90.7% respectively while the characteristics for cow dung were 67.2, 32.8 and 96.0 % respectively. From the study, a mixing ratio of cow dung: food waste of 1:2 was found to be the optimum substrate mixture for biogas production at 25595.7 Nml. The accumulated gas volumes of 18756.6, 14042.5, 13940.8 and 13839.1 Nml were recorded for cow dung: food waste ratios of 2:1, 1:1, 1:3 and 3:1 respectively. For a co-digestion containing more of the food waste than cow dung, a higher volume of biogas is produce.
Formulation and simulation of a hybrid solar PV-wind generation system with photovoltaic concentration for non-interconnected areas to the energy grid
Authors: Torres-Madroñero José Luis , Tamayo-Avendaño Jorge Mario , Bernal-del Río Santiago , Sierra-Pérez Julián , Nieto-Londoño César , Mejía-Gutiérrez Ricardo , Osorio-Gómez Gilberto
Published: July 2020

Different isolated systems with conventional generation sources are installed in Non-Interconnected Areas (ZNI) in Colombia while off-grid renewable systems are a trending answer for the energy supply in these regions. The complementarity between different energy sources, a storage system and adequate control can substantially improve the reliability of isolated generation systems. In this context, the sizing of a Hybrid Renewable Energy System (HRES) by means of a Genetic Algorithm (GA) is presented, considering the wind and solar resources specific to a representative rural location in Colombia. The methodology involves power curves for small wind turbines and the model for photovoltaic solar panels. The preliminary output consists of a weighted distribution for each technology, either wind or conventional photovoltaics, and is constrained by the Loss of Power Supply Probability (LPSP) and the Levelized Cost Of Electricity (LCOE). A second step consists of the optimization of the installed area for photovoltaic generation, considering a Concentrated Photovoltaic (CPV) system and aiming to maintain the initial fraction of generation for this resource. Finally, an analysis is performed on the reduction of area for solar generation to the increase in costs derived from the use of concentrators and other penalties associated with this technology.
Cardiac Echocardiography in COVID-19 Infection
Authors: Kapur Rohan , Garg Naveen , Kapur K. K. , Kapoor Pranav , Kapoor Poonam Malhotra
Published: July 2020

The novel COVID-19 disease mainly affects respiratory organs; however, involvement of cardiovascular system is also not uncommon. Cardiac involvement can manifest as myocarditis, heart failure, myocardial infarction, pulmonary embolism, or arrhythmias in COVID-19 patients. This novel Coronavirus enters into the cells of the human body by binding to ACE-2 receptors which are predominantly present on pneumocytes and cardiomyocytes. The damage to myocardium is manifested by the increase in cardiac enzymes such as troponin-I, CK-MB, and NT pro-BNP. Although echocardiogram is an important tool in the cardiac evaluation of COVID-19 patients, its indiscriminate use is discouraged, owing to the risk of transmission to echocardiography service providers, as well as possible risk of contaminating echocardiography equipment. In this article, we discuss the different mechanisms and cardiac manifestations of COVID-19. We also review the current guidelines for echocardiography evaluation of COVID-19 patients as well as current recommendations on safety of echocardiography personnel and equipment against contamination. We also include our experience of two cases in which COVID-19 affliction of heart was strongly suspected, and echocardiography clinched the diagnosis.
Occult Esophageal Squamous Cell Carcinoma Presenting with Multiple Bony Osteolytic Lesions Clinically Mimicking Multiple Myeloma: A Diagnostic Dilemma
Authors: Lyngdoh Bifica Sofia , Dey Biswajit , Raphael Vandana , Tiewsoh Iadarilang
Published: July 2020

Bone metastasis as an initial presentation of esophageal carcinoma is uncommon. In the absence of typical presentations like dysphagia, these cases may lead to diagnostic dilemmas both for the clinicians and pathologists. Here, we report a case of disseminated metastasis of esophageal squamous cell carcinoma to the bone in a 47-year-old female, who presented with multiple osteolytic lesions and clinically mimicking multiple myeloma. A detailed diagnostic work-up established the diagnosis of esophageal squamous cell carcinoma.
Antithrombotic Therapy in Myocardial Infarction: Historic Perils and Current Challenges—A 70-Year Journey
Authors: Stub Dion , Fernando Himawan , McFadyen James D. , Palasubramaniam Jathushan , Shaw James , Wang Xiaowei , Peter Karlheinz
Published: July 2020

There have been numerous and intriguing advancements in antithrombotic therapy for myocardial infarction since it was described in the earliest issues of Thrombosis and Haemostasis. In this article, we revisit historical breakthroughs and describe the four most challenging contemporary themes relating to antithrombotic therapy in myocardial infarction. In all four, the challenge is to find the best balance of reducing specific levels of ischaemic risks without increasing bleeding risk. The first is the question of the optimal duration of dual antiplatelet therapy (DAPT) after percutaneous coronary intervention (PCI). This includes discussion of monotherapy after a period of DAPT. The second relates to the role of genotype and phenotype-guided individualisation of antiplatelet therapy. There is emerging evidence for a role of pheno/genotyping in identifying individuals at high risk for recurrent ischaemic events or in guiding the timing of cardiac surgery for patients on DAPT. The third addresses the increasing evidence for dual pathway inhibition, for example, with rivaroxaban in addition to aspirin in patients where high ischaemic and low bleeding risk is demonstrated. Finally the fourth highlights the challenge of the most appropriate combination of antiplatelet and anticoagulation therapy for patients with known atrial fibrillation after PCI. In most individuals, oral P2Y12 inhibitor therapy combined with a direct acting oral anticoagulant appears to be the best strategy based on the available evidence. Overall, the progress in antithrombotic therapy achieved over the last seven decades is remarkable, however, there are important issues to address and progress still to be made.
Evaluation of Angiogenesis in Multiple Myeloma by VEGF Immunoexpression and Microvessel Density
Authors: Palta Anshu , Kaur Manveen , Tahlan Anita , Dimri Kislay
Published: July 2020

Background Multiple myeloma (MM) is a plasma cell disorder characterized by monoclonal proliferation of plasma cells in bone marrow. Plasmablastic MM is a morphologic subset of MM, containing ≥2% plasmablasts of all plasma cells.

Methods The study included 30 consecutively diagnosed patients of MM (6 plasmablastic, 24 nonplasmablastic) over a span of 2 years. Angiogenesis in MM was assessed by analysis of vascular endothelial growth factor (VEGF) immunoexpression by plasma cells and microvessel density (MVD) using anti-CD34 antibody. CD34 and VEGF immunohistochemical staining was performed in all the 30 cases. Angiogenesis was studied in relation to plasmablastic morphology and clinical profile to determine if any correlation exists between these.

Results The mean VEGF expression of 80.83 ± 7.36 in plasmablastic myeloma cases was significantly higher compared with a mean VEGF of 53.54 ±17.09 in nonplasmablastic cases. Most of the cases (66.6%) of plasmablastic myeloma exhibited strong (3+) VEGF expression. The difference in mean VEGF expression between plasmablastic and nonplasmablastic cases was found to be statistically significant (p = 0.001). The mean MVD in plasmablastic cases was 44.8 ± 3.69, while in the nonplasmablastic category, the mean MVD was 23.7 ± 5.14, difference being statistically significant (p < 0.05). Also, a positive correlation was found between VEGF expression and MVD.

Conclusion A moderate/strong VEGF intensity and higher MVD were found in cases of plasmablastic MM, suggesting that a more aggressive histological disease may be associated with increased production of VEGF. This finding might be helpful to identify a subset of patients with adverse prognosis and to provide antiangiogenic therapy to improve their survival. However, studies comprising larger number of patients are required to bring out a statistical significance to further substantiate these findings.
An endpoint case of the renormalization property for the relativistic Vlasov–Maxwell system
Authors: Nguyen Thanh-Nhan , Tran Minh-Phuong
Published: July 2020

The aim of this paper is to improve the previous work on the relativistic Vlasov–Maxwell system, one of the most important equations in plasma physics. Recently, Bardos et al. [Q. Appl. Math. 78, 193–217 (2020)] presented a proof of an Onsager type conjecture on the renormalization property and the entropy conservation laws for the relativistic Vlasov–Maxwell system. Particularly, the authors proved that if the distribution function u∈L∞(0,T;Wθ,p(R6)) and the electromagnetic field E,B∈L∞(0,T;Wκ,q(R3)) with θ, κ ∈ (0, 1) such that θκ + κ + 3θ − 1 > 0 and 1/p + 1/q ≤ 1, then the renormalization property and entropy conservation laws hold. To determine a complete proof of this work, in this paper, we improve their results under weaker regularity assumptions for a weak solution to the relativistic Vlasov–Maxwell equations. More precisely, we show that under similar hypotheses, the renormalization property and entropy conservation laws for the weak solution to the relativistic Vlasov–Maxwell system even hold for the endpoint case θκ + κ + 3θ − 1 = 0. Our proof is based on better estimations on regularization operators.
Cellulose in ionic liquid solution as a potential synthetic polymer substitute
Authors: Larter Raima
Published: July 2020

Cellulose dissolved in ionic liquids could be a sustainable system with great industrial potential, but applications have been hampered by its complex behavior in solution.
NH2-MIL-53(Al) for simultaneous removal and detection of fluoride anions
Authors: Xie Dong-hua , Ge Xiao , Qin Wen-xiu , Zhang Yun-xia
Published: July 2020

To address the limitations of the separate fluoride removal or detection in the existing materials, herein, amino-decorated metal organic frameworks NH2-MIL-53(Al) have been succinctly fabricated by a sol-hydrothermal method for simultaneous removal and determination of fluoride. As a consequence, the proposed NH2-MIL-53(Al) features high uptake capacity (202.5 mg/g) as well as fast adsorption rate, being capable of treating 5 ppm of fluoride solution to below the permitted threshold in drinking water within 15 min. Specifically, the specific binding between fluoride and NH2-MIL-53(Al) results in the release of fluorescent ligand NH2-BDC, conducive to the determination of fluoride via a concentration-dependent fluorescence enhancement effect. As expected, the resulting NH2-MIL-53(Al) sensor exhibits selective and sensitive detection (with the detection limit of 0.31 µmol/L) toward fluoride accompanied with a wide response interval (0.5−100 µmol/L). More importantly, the developed sensor can be utilized for fluoride detection in practical water systems with satisfying recoveries from 89.6% to 116.1%, confirming its feasibility in monitoring the practical fluoride-contaminated waters.
Topological transition in monolayer blue phosphorene with
transition-metal adatom under strain
Authors: Hu Ge , Hu Jun
Published: July 2020

We carried out first-principles calculations to investigate the electronic properties of the monolayer blue phosphorene (BlueP) decorated by the group-IVB transition-metal adatoms (Cr, Mo and W), and found that the Cr-decorated BlueP is a magnetic half metal, while the Mo- and W-decorated BlueP are semiconductors with band gaps smaller than 0.2 eV. Compressive biaxial strains make the band gaps close and reopen, and band inversions occur during this process, which induces topological transitions in the Mo-decorated BlueP (with strain of −5.75%) and W-decorated BlueP (with strain of −4.25%) from normal insulators to topological insulators (TIs). The TI gap is 94 meV for the Mo-decorated BlueP and 218 meV for the W-decorated BlueP. Such large TI gaps demonstrate the possibility to engineer topological phases in the monolayer BlueP with transition-metal adatoms at high temperature.
Doping copper ions in a metal-organic framework (UiO-66-NH2):
Location effect examined by ultrafast spectroscopy
Authors: Liu Jia , Jiang Shen-long , Zhang Qun
Published: July 2020

We constructed two types of copper-doped metal-organic framework (MOF), i.e., Cu@UiO- 66-NH2 and Cu-UiO-66-NH2. In the former, Cu2+ ions are impregnated in the pore space of the amine-functionalized, Zr-based UiO-66-NH2; while in the latter, Cu2+ ions are in-corporated to form a bimetal-center MOF, with Zr4+ being partially replaced by Cu2+ in the Zr−O oxo-clusters. Ultrafast spectroscopy revealed that the photoinduced relaxation kinetics associated with the ligand-to-cluster charge-transfer state is promoted for both Cu-doped MOFs relative to undoped one, but in a sequence of Cu-UiO-66-NH2>Cu@UiO-66-NH2>UiO-66-NH2. Such a sequence turned to be in line with the trend observed in the visible-light photocatalytic hydrogen evolution activity tests on the three MOFs. These findings highlighted the subtle effect of copper-doping location in this Zr-based MOF system, further suggesting that rational engineering of the specific metal-doping location in alike MOF systems to promote the photoinduced charge separation and hence suppress the detrimental charge recombination therein is beneficial for achieving improved performances in MOF-based photocatalysis.
Impact of structural disorder on excitonic behaviors and dynamics in
2D organic-inorganic hybrid perovskites
Authors: Li Xiao-xia , Jiang Shen-long , Zhang Qun
Published: July 2020

Two thin-film 2D organic-inorganic hybrid perovskites, i.e., 2-phenylethylammonium lead iodide (PEPI) and 4-phenyl-1-butylammonium lead iodide (PBPI) were synthesized and investigated by steady-state absorption, temperature-dependent photoluminescence, and temperature-dependent ultrafast transient absorption spectroscopy. PBPI has a longer organic chain (via introducing extra ethyl groups) than PEPI, thus its inorganic skeleton can be distorted, bringing on structural disorder. The comparative analyses of spectral profiles and temporal dynamics revealed that the greater structural disorder in PBPI results in more defect states serving as trap states to promote exciton dynamics. In addition, the fine-structuring of excitonic resonances was unveiled by temperature-dependent ultrafast spectroscopy, suggesting its correlation with inorganic skeleton rather than organic chain. Moreover, the photoexcited coherent phonons were observed in both PEPI and PBPI, pointing to a subtle impact of structural disorder on the low-frequency Raman-active vibrations of inorganic skeleton. This work provides valuable insights into the optical properties, excitonic behaviors and dynamics, as well as coherent phonon effects in 2D hybrid perovskites.
High and reversible spin polarization in a collinear antiferromagnet
Authors: Tong Junwei , Luo Feifei , Ruan Liuxia , Qin Gaowu , Zhou Lianqun , Tian Fubo , Zhang Xianmin
Published: July 2020

Antiferromagnetic materials are expected to trigger the revolution of spintronic applications because they are robust against the perturbation of magnetic fields, produce no stray fields, and display ultrafast dynamics. To design antiferromagnetic devices, the generation and manipulation of spin-polarized current in antiferromagnetic materials are vital. Unfortunately, it has long been believed that spin-polarized current could not be achieved in collinear antiferromagnetic materials because of the symmetry of spin sublattices. Inspired by the possibility of breaking the symmetry using a bias voltage, a special Au/NiO/Au junction is proposed and constructed along the [111] direction of NiO using the collinear NiO antiferromagnetic insulator as a prototype. It was found that the symmetry of spin sublattices was broken by an external bias, which induces a nonequivalent transport for spin-up and spin-down currents, that is, the appearance of spin-polarized current. Unexpectedly, this study found that the magnitude and sign of spin polarization could be adjusted by varying the bias. A positive spin polarization up to 80% was obtained at ∼ 0.9 V, and the spin polarization turned negative when the bias voltage was beyond 1.6 V. The related physical mechanisms were explored and clarified by analyzing spin-resolved transmission, kǁ-resolved density of states, and layer-resolved local density of states of Au/NiO/Au, etc. The effects of NiO layer thicknesses, different electrodes, and interfacial disorders on the spin polarization were also analyzed and found to offer promising applications. This study provides new physical insight into spin-polarized current transport in collinear antiferromagnetic materials and greatly contributes to the development of novel antiferromagnetic spintronic devices.
Acoustic radiation force and motion of a free cylinder in a viscous fluid with a boundary defined by a plane wave incident at an arbitrary angle
Authors: Qiao Yupei , Zhang Xiaowei , Gong Menyang , Wang Haibin , Liu Xiaozhou
Published: July 2020

The acoustic radiation force (ARF) is derived for a free cylinder immersed in a viscous fluid with a boundary defined by a plane wave incident at an arbitrary angle. Trajectories of a free rigid cylinder under the action of ARF are also investigated. Various aspects affecting the ARFs and trajectories of a free rigid cylinder, such as fluid viscosity, the incident angle of the plane wave, the density ratio of the fluid to particle, the particle radius, and boundary, are addressed in numerical simulations. Results show that ARFs are positive or negative depending on the various factors considered in this work. Moreover, the amplitude of the total ARF on a free cylinder in a bounded viscous fluid defined by a plane wave incident at a certain angle may decrease with increasing viscosity, which is significantly different from the case of a fixed cylinder immersed in a boundless viscous fluid. Furthermore, the trajectory of the particle changing with different conditions is investigated. We can predict and regulate the particle trajectory by selecting relevant parameters. The finite element method is implemented to validate the theoretical results. The finite element results and theoretical results are in good agreement. This work helps better understand the underlying mechanism of the particle manipulation using ARF.
First-principles study of the catalytic properties of Co-doped molybdenum disulfide nanoribbons for the hydrogen evolution reaction
Authors: Sun Yuzhuo , Li Chenjia , Zhang Jinduo , Feng Luyao , Zhang Yongze , Chang Junshi , Shi Lijie , Wang Xiaoyuan
Published: July 2020

Molybdenum disulfide has attracted significant research attention as a nanocatalyst for hydrogen evolution reaction. In this study, the effects of nanoribbons on the catalytic performance of molybdenum disulfide in the hydrogen evolution reaction are evaluated via the density functional theory. Co is considered to be an effective promoter of Mo-based catalysts. Thus, the promotion of the Mo-edge was studied here in a number of Co-substituted surface models. The results show that the electronic structure of the molybdenum disulfide nanoribbons changed after doping with Co atoms; this change significantly reduced the Gibbs free energy of the hydrogen evolution reaction and improved the reaction activity. In addition, the effects of stress regulation on the catalyst were analyzed. Tensile and compressive stresses were applied to the catalyst in the x direction. The results indicate that the distance between atoms changed owing to the effects of stress, and changes were also observed in the electronic properties. The insights obtained from this study will be helpful to further improve the activity of catalysts.
Measurement of the heat flux normalized spin Seebeck coefficient of thin films as a function of temperature
Authors: Venkat G. , Cox C. D. W. , Sola A. , Basso V. , Morrison K.
Published: July 2020

The spin Seebeck effect (SSE) has generated interest in the thermoelectric and magnetic communities for potential high efficiency energy harvesting applications and spintronic communities as a source of pure spin current. Understanding the underlying mechanisms requires characterization of potential materials across a range of temperatures; however, for thin films, the default measurement of an applied temperature gradient (across the sample) has been shown to be compromised by the presence of thermal resistances. Here, we demonstrate a method to perform low temperature SSE measurements where, instead of monitoring the temperature gradient, the heat flux passing through the sample is measured using two calibrated heat flux sensors. This has the advantage of measuring the heat loss through the sample as well as providing a reliable method to normalize the SSE response of thin film samples. We demonstrate this method with an SiO2/Fe3O4/Pt sample where a semiconducting–insulating transition occurs at the Verwey transition, TV, of Fe3O4 and quantify the thermomagnetic response above and below TV.
Dynamics and spectroscopy of molecular ensembles in a lossy microcavity
Authors: Ulusoy Inga S. , Vendrell Oriol
Published: July 2020

The radiative and nonradiative relaxation dynamics of an ensemble of molecules in a microcavity are investigated with emphasis on the impact of the cavity lifetime on reactive and spectroscopic properties. Extending a previous study [I. S. Ulusoy et al., J. Phys. Chem. A 123, 8832–8844 (2019)], it is shown that the dynamics of the ensemble and of single molecules are influenced by the presence of a cavity resonance as long as the polariton splitting can be resolved spectroscopically, which critically depends on the lifetime of the system. Our simulations illustrate how the branching between nonradiative intersystem crossing and radiative decay through the cavity can be tuned by selecting specific cavity photon energies resonant at specific molecular geometries. In the case of cavity–photon energies that are not resonant at the Franck–Condon geometry of the molecules, it is demonstrated numerically and analytically that collective effects are limited to a handful of molecules in the ensemble.
Thermal transport enhancement of hybrid nanocomposites; impact of confined water inside nanoporous silicon
Authors: Isaiev Mykola , Wang Xiaorui , Termentzidis Konstantinos , Lacroix David
Published: July 2020

The thermal transport properties of porous silicon and nano-hybrid “porous silicon/water” systems are presented here. The thermal conductivity was evaluated using the equilibrium molecular dynamics technique for porous systems made of spherical voids or water-filled cavities. We revealed large thermal conductivity enhancement in the nano-hybrid systems as compared to their dry porous counterparts, which cannot be captured by effective media theory. This rise of thermal conductivity is related to the increase in the specific surface area of the liquid/solid interface. We demonstrated that the significant difference, more than two folds, in thermal conductivity of pristine porous silicon and “porous silicon liquid–composite” is due to the liquid density fluctuation close to the “solid–liquid interface” (layering effect). This effect is getting more importance for the large specific surface of the interfacial area. Specifically, the enhancement of the effective thermal conductivity is 50% for a specific surface area of 0.3 (1/nm), and it increases further upon the increase in the surface to volume ratio. Our study provides valuable insights into the thermal properties of hybrid liquid/solid nanocomposites and into the importance of confined liquids within nanoporous materials.
A study on compensatory scattering correction of industrial γ-photon 3D imaging method
Authors: Zhao Min , Sun Tong , Yao Min , Guo Ruipeng , Jiang Tao , Zhao Zenghao , Li Yuhui
Published: July 2020

As a non-destructive testing technology, γ-photon imaging technology has a good application prospect in the industrial field. However, due to the γ-photon scattering problem caused by high-density metal and the rapid industrial detection requirement, γ-photon imaging technology has not been effectively applied in industrial detection. Thus, this paper proposed a compensatory single scatter simulation (C-SSS) and combined it with the 3D ordered subset expectation maximization (3D-OSEM) image reconstruction algorithm for optimization to solve the above problems. To verify the effectiveness of the C-SSS algorithm, this paper compared C-SSS with the single scatter simulation by two types of phantoms and the inner cavity detection of industrial components. The comparison results proved that C-SSS can effectively improve the measurement accuracy and reduce the scanning time. In addition, after the algorithm code was optimized and accelerated by the graphic processing unit, the execution time of C-SSS was ∼4 min and a single iteration of 3D-OSEM took ∼3 min, basically satisfying the requirements of rapid industrial detection. Simulation and experiment results show the potential of the proposed algorithm in industrial detection.
The Winfree model with non-infinitesimal phase-response curve: Ott–Antonsen theory
Authors: Pazó Diego , Gallego Rafael
Published: July 2020

A novel generalization of the Winfree model of globally coupled phase oscillators, representing phase reduction under finite coupling, is studied analytically. We consider interactions through a non-infinitesimal (or finite) phase-response curve (PRC), in contrast to the infinitesimal PRC of the original model. For a family of non-infinitesimal PRCs, the global dynamics is captured by one complex-valued ordinary differential equation resorting to the Ott–Antonsen ansatz. The phase diagrams are thereupon obtained for four illustrative cases of non-infinitesimal PRC. Bistability between collective synchronization and full desynchronization is observed in all cases.
Flow-induced fractionation effects on slip of polydisperse polymer melts
Authors: Najm Marina , Hatzikiriakos Savvas G.
Published: July 2020

The slip behavior of several high-density polyethylenes with a broad range of molecular weights (MWs) including bimodal is studied as a function of MW and its distribution (MWD). A formulation inspired by the reptation theory is used to predict the slip velocity of the studied polymers as a function of MWD coupled with a model of surface MW fractionation that includes (i) the entropy driven migration of short chains toward the die wall due to the concentration gradient and (ii) the flow (stress)-induced migration effects. While surface fractionation has a minor effect on slip of narrow to moderate MWD polymers (particularly unimodal), its role is significant for broad bimodal MWD polymers. The inclusion of both effects (concentration and flow gradients) accurately captures the slip velocity of broad MWD polymers.
Optomechanical interaction in fibre lasers with micro-optomechanical resonance structures
Authors: Egorov F.A. , Potapov V.T.
Published: July 2020

We report the results of studies of fibre lasers with passive modulators based on light-excited micro-optomechanical resonance structures (micro-oscillators). It is shown that in fibre lasers based on active fibres doped with rare-earth elements (Er, Er/Yb, Yb, Nd), the optomechanical interaction of laser radiation with micro-oscillators of various types (fibre-optic, microvolume) leads to self-oscillations of the characteristics of laser radiation at frequencies of relaxation oscillations and intermode beats synchronised with the frequencies of elastic eigenoscillations of micro-oscillators. It is found that in an ultra-long erbium – ytterbium fibre laser with a nonlinear mirror based on a microcantilever, laser photothermal excitation of the second mode of elastic transverse oscillations of the microcantilever makes it possible to perform passive mode locking exclusively due to Q-switching of the laser cavity. Pulsed lasing with a controlled repetition rate (∼76 kHz), a pulse duration of 2 – 5 μs and an output energy of 0.1 μJ per pulse is implemented. Based on a simplified physical model of the indicated fibre lasers with micro-oscillators, we have developed an approximate mathematical model describing the regimes of passive mode locking of fibre lasers with micro-oscillators that play the role of mirrors with a nonlinear reflection coefficient in the laser cavity. The prospects for the development and application of the considered laser systems are discussed.
Effect of focused nanosecond laser pulse irradiation on microtribological properties of diamond-like films
Authors: Frolov V.D. , Pivovarov P.A. , Zavedeev E.V. , Shupegin M.L. , Pimenov S.M.
Published: July 2020

We have examined the effect of focused nanosecond laser pulses on the formation and tribological properties of microstructures in the form of a matrix of craters produced in a – C : H : Si : O diamond-like films (DLFs), both undoped and doped with tungsten. The studies are performed by scanning probe microscopy (SPM) using SPM probes of standard design with a tip and probes without a tip (tipless-type probes). A special procedure is developed for assessing the wettability (contact angle) of individual sections of the laser-induced microstructure by the local adhesion force. According to estimates, the material inside the crater becomes softer and more hydrophobic as a result of laser irradiation. This is manifested to the greatest extent in tungsten-doped DLFs, where the crater walls are arranged like terraces formed by ‘nanoflakes’, i.e. grains of the substance. Scanning of microstructures with a tipless probe in the regime of lateral force microscopy demonstrates a decrease in friction in the crater area.
Influence of growth temperature of KTiOAsO4 single crystals on their physicochemical parameters and formation of domain structures
Authors: Isaenko L.I. , Eliseev A.P. , Kolker D.B. , Vedenyapin V.N. , Zhurkov S.A. , Erushin E.Yu. , Kostyukova N.Yu. , Boiko A.A. , Shur V.Ya. , Akhmatkhanov A.R. , Chuvakova M.A.
Published: July 2020

A potassium titanyl arsenate (KTiOAsO4, KTA) crystal 50 × 80 × 60 mm in size has been grown by upgraded Czochralski method from flux (TGGS) with a decrease in temperature from 900 to 770 °C during pulling. It is shown that the spectroscopic properties of the parts of KTA crystals grown at 900 and 770 °C are close, whereas the electrical conductivity of the low-temperature (770 °C) KTA part turned out to be an order of magnitude lower than that of the high-temperature part. Visualisation of the domain structure by second-harmonic generation microscopy revealed a more efficient domain intergrowth (throughout the sample) in the low-temperature KTA, which is important for forming a regular domain structure (RDS) in a KTA-based nonlinear optical element. It is established that the quantum efficiency of parametric generation of light in the RDS formed in low-temperature KTA is several times higher than in the case of high-temperature KTA. The results obtained are important for optimising RDS parameters.
Experimental investigation of laser ablation of stone polycrystalline targets
Authors: Burdonskii I.N. , Leonov A.G. , Makarov K.N. , Yufa V.N.
Published: July 2020

We report the results of an experimental investigation of ablation of stone polycrystalline targets of complex multicomponent composition, which imitate the substance of asteroids. The targets were irradiated by nanosecond pulses of a neodymium laser at an energy density Φ
L of up to 5 × 104 J cm−2. The experiments demonstrated the existence of two ablation regimes, with the boundary between them lying at Φ
L ≈ 4000 J cm−2. The regime change is characterised by a change in the form of the dependence of the surface mass density of removed target material on the laser energy density and by the appearance of a minimum in the dependence of specific energy of destruction on Φ
L. This is supposedly related to the passage from a one-dimensional plasma plume expansion to the three-dimensional one and the corresponding decrease in the efficiency of energy transfer from the laser beam to the target due to a lowering of laser-produced plasma density. Our experiments also showed the existence of a maximum in impulse coupling coefficient C
m as a function of laser energy density (C
m ≈ 6.3 × 10−5 N W−1 for Φ
L = Φ
opt ≈ 25 J cm−2). Maxima were also recorded in the dependences of the ablation efficiency and average ablation flow velocity on Φ
L. For Φ
L > Φ
opt, the decrease in the function C
m(Φ
L) turns out to be much steeper than for metals and polymer materials. The difference is supposedly due to the lower strength and lower plasticity of the polycrystalline stone targets.
Leaky wave in high-power AlGaAs/InGaAs/GaAs semiconductor lasers
Authors: Bobretsova Yu.K. , Veselov D.A. , Klimov A.A. , Kryuchkov V.A. , Shashkin I.S. , Slipchenko S.O. , Pikhtin N.A.
Published: July 2020

Lasers based on AlGaAs/InGaAs/GaAs heterostructures operating in the spectral range of 1.0 − 1.1 μm are investigated in order to optimise cladding layers. The effect of the thickness and composition of the cladding layers on the leakage of radiation from the laser waveguide is analysed. It is shown that for cladding thicknesses of 0.86 − 1.24 μm, it almost does not affect the output optical power. The effect of the crystal length and reflectivity of the laser mirrors on the leaky wave is demonstrated.
Lasing characteristics of ZrO2 − Y2O3 − Ho2O3 crystals pumped by a Tm : LiYF4 laser
Authors: Ryabochkina P.A. , Artemov S.A. , Zakharov N.G. , Saltykov E.V. , Vorontsov K.V. , Chabushkin A.N. , Lomonova E.E.
Published: July 2020

Two-micron lasing is obtained on the 5I7 → 5I8 transition of Ho3+ ions in ZrO2 − Y2O3 −Ho2O3 crystals upon resonance pumping into the 5I7 level of these ions by a pulsed laser based on a Tm : LiYF4 crystal. The efficiency of conversion of pump radiation incident on the crystal to laser radiation and the slope lasing efficiency at a pulse duration of 8 ms and a pulse repetition rate of 10 Hz were 25% and 28%, respectively.
Effect of finite ion mass on relativistic self-induced transparency of plasma layers with a sharp boundary
Authors: Mikheitsev N.A. , Korzhimanov A.V.
Published: July 2020

We consider the effect of ion mobility on the threshold of relativistic self-induced transparency under irradiation of thin plasma layers by circularly polarised laser radiation. An analytical model of the motion of ions during the removal of electrons from the layer surface by the ponderomotive force of laser radiation is constructed. The model is used to analyse the motion of probe electrons in the resulting electromagnetic field. It is shown that the higher the ion mobility and the longer the laser pulse, the more stable the plasma layer to longitudinal perturbations of a finite value and the higher the threshold of self-induced transparency. These conclusions are verified by one-dimensional numerical simulation of a complete system of kinetic equations for plasma and Maxwell’s equations.
Stochastic bacterial population dynamics restrict the establishment of antibiotic resistance from single cells
Authors: Alexander Helen K. , MacLean R. Craig
Published: July 2020

Significance

The emergence of antibiotic resistance poses a critical threat to the efficacy of antibiotic treatments. A resistant bacterial population must originally arise from a single cell that mutates or acquires a resistance gene. This single cell may, by chance, fail to successfully reproduce before it dies, leading to loss of the nascent resistant lineage. Here, we show that antibiotic concentrations that selectively favor resistance are nonetheless sufficient to reduce the chance of outgrowth from a single cell to a very low probability. Our findings suggest that lower antibiotic concentrations than those required to clear a large resistant population may be sufficient to prevent, with high probability, outgrowth of initially rare resistant mutants.
General learning ability in perceptual learning
Authors: Yang Jia , Yan Fang-Fang , Chen Lijun , Xi Jie , Fan Shuhan , Zhang Pan , Lu Zhong-Lin , Huang Chang-Bing
Published: July 2020

Significance

Developing expertise usually requires acquisition of a variety of skills, and some can become experts and some can’t. The ubiquitous individual differences in perceptual learning led us to hypothesize that each individual has a general perceptual learning “ability,” and individual differences reflect the variability of such ability across individuals. By collecting and analyzing data from a large sample of subjects in seven visual, auditory, and working memory training tasks, we successfully extracted both a task-specific but subject-invariant component of learning and a subject-specific but task-invariant perceptual learning ability. The existence of a general learning ability could have important implications for theories and applications of perceptual learning across multiple tasks and the development of perceptual expertise and/or remediation of visual conditions.
Mitochondria-lysosome contacts regulate mitochondrial Ca2+dynamics via lysosomal TRPML1
Authors: Peng Wesley , Wong Yvette C. , Krainc Dimitri
Published: July 2020

Significance

Mitochondria and lysosomes are critical for cellular homeostasis and defects in both organelles are observed in several diseases. Recently, contact sites between mitochondria and lysosomes were identified and found to modulate mitochondrial dynamics. However, whether mitochondria–lysosome contacts have additional functions is unknown. Here, we identify a function of mitochondria–lysosome contacts in facilitating the direct transfer of calcium from lysosomes to mitochondria. Transfer of calcium at mitochondria–lysosome contacts is mediated by the lysosomal channel TRPML1 and is disrupted in mucolipidosis type IV, a lysosomal storage disorder caused by loss-of-function mutations in TRPML1. Calcium transfer from lysosomes to mitochondria at mitochondria–lysosome contacts thus presents an additional mechanism of intracellular calcium regulation that may further contribute to various disorders.
The changing landscape of unofficial signage in a U.S. refugee relocation city
Authors: Yochim Ashley
Published: July 2020

This Linguistic Landscape project investigates public signage throughout one year in a small Pennsylvania refugee
relocation city, exploring the linguistic diversity of the city’s numerous generations of newcomers. The diachronic analysis
indicates that monolingual government signs conflict with multilingual signs in private businesses, demonstrating that newcomer
business owners are willing to meet the needs of refugees and immigrants even if the government will not. The lack of official
multilingual signage calls into question what obligation government city planners in refugee relocation areas have to accommodate
their linguistically diverse newcomers. The results of this project also reveal that the Linguistic Landscape is dynamic, as
suggested by new languages that are layered on top of evidence of earlier generations of immigrants and by changes to signs within
one year.
Inducing ferromagnetism in surface stabilised intrinsic CdSe nanoparticles by a simple process
Authors: Pokhriyal Sumit , Biswas Somnath
Published: July 2020

In this letter, we report a simple process to derive in situ surface stabilised intrinsic CdSe nanoparticles (NPs) showing room temperature ferromagnetism (RTFM). The observed RTFM is primarily attributed to the lattice strain ( ε) in the NPs supported by an effective core (CdSe)-shell (surface layer) charge transfer mechanism. The synthesis method allows precise control over particle morphology and dispersity, and is highly convenient in tuning the magnetic properties for pertinent applications.

Highlights Magnetic CdSe nanoparticles were synthesized by a facile process. In situ formed graphitic-carbon layer on the surface stabilises the nanoparticles. The process permits precise control over particle morphology and dispersity. The technique is also convenient in tuning the magnetic properties. Monodispersed magnetic CdSe nanoparticles have potential applications in modern optoelectronics.

GRAPHICAL ABSTRACT
Ginsenoside Rg2 attenuates myocardial fibrosis and improves cardiac function after myocardial infarction via AKT signaling pathway
Authors: Li Xianghai , Xiang Ning , Wang Zhengrong
Published: July 2020

With the popularization of percutaneous coronary intervention technology in clinical applications, the mortality rate of acute myocardial infarction has been significantly reduced. However, ventricular remodeling following myocardial infarction (MI) has attracted extensive attention for that it can cause malignant arrhythmia, heart failure, and even death. We aimed to investigate the effects of ginsenoside Rg2 on cardiac function and myocardial fibrosis after MI and its potential mechanism. The results demonstrated that ginsenoside Rg2 improved cardiac function and inhibited collagen deposition in mice after MI. In addition, ginsenoside Rg2 reduced the levels of fibrosis-associated genes Collagen I (Col 1), Collagen III (Col 3), and alpha-smooth muscle actin (α-SMA) by activating phosphorylated AKT in angiotensin II–induced cardiac fibroblasts. Taken together, ginsenoside Rg2 improves cardiac function and attenuates cardiac fibrosis via the AKT pathway, suggesting that ginsenoside Rg2 may be a promising drug for the prevention of ventricular remodeling after MI.

Abbreviations: MI: myocardial infarction; AMI: acute myocardial infarction; LAD: left anterior descending; ECM: extracellular matrix; Col 1: collagen I; Col 3: collagen III; α-SMA: alpha-smooth muscle actin; ROS: reactive oxygen species; SOD: superoxide dismutase; GSH: glutathione; HO-1: heme oxygenase-1; WST8: water-soluble tetrazolium salt 8.
mRNA localization mediates maturation of cytoplasmic cilia in Drosophila spermatogenesis
Authors: Fingerhut Jaclyn M. , Yamashita Yukiko M.
Published: July 2020

Cytoplasmic cilia, a specialized type of cilia in which the axoneme resides within the cytoplasm rather than within the ciliary compartment, are proposed to allow for the efficient assembly of very long cilia. Despite being found diversely in male gametes (e.g., Plasmodium falciparum microgametocytes and human and Drosophila melanogaster sperm), very little is known about cytoplasmic cilia assembly. Here, we show that a novel RNP granule containing the mRNAs for axonemal dynein motor proteins becomes highly polarized to the distal end of the cilia during cytoplasmic ciliogenesis in Drosophila sperm. This allows for the incorporation of these axonemal dyneins into the axoneme directly from the cytoplasm, possibly by localizing translation. We found that this RNP granule contains the proteins Reptin and Pontin, loss of which perturbs granule formation and prevents incorporation of the axonemal dyneins, leading to sterility. We propose that cytoplasmic cilia assembly requires the precise localization of mRNAs encoding key axonemal constituents, allowing these proteins to incorporate efficiently into the axoneme.
Predicting the Potential Performance in P-Type SnS Crystals via Utilizing the Weighted Mobility and Quality Factor
Authors: He Wenke , Qin Bingchao , Zhao Li-Dong
Published: July 2020

The figure of merit ZT is the direct embodiment of thermoelectric performance for a given material. However, as an indicator of performance improvement, the only ZT value is not good enough to identify its outstanding inherent properties, which are highly sought in thermoelectric community. Here, we utilize one powerful parameter to reveal the outstanding properties of a given material. The weighted mobility is used to estimate the carrier transports of p-type SnS crystals, including the differences in doping level, carrier scattering and electronic band structure. We analyze the difference in carrier scattering mechanism for different crystal forms with the same doping level, then evaluate and confirm the temperature-dependent evolution of electronic band structures in SnS. Finally, we calculate the quality factor B based on the weighted mobility, and establish the relationship between ZT and B to further predict the potential performance in p-type SnS crystals with low cost and earth abundance, which can be realized through taking advantage of the inherent material property, thus improving B factor to achieve optimal thermoelectric level.