bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation of intense coherent electromagnetic radiation during the interaction of a multi-terawatt laser pulse with a nanowire target*
Authors: Kulagin V.V. , Kornienko V.N. , Cherepenin V.A. , Gupta D.N. , Suk H. 
Published: March 2021

Abstract
Generation of coherent radiation in the IR and terahertz ranges during the propagation of a multi-terawatt laser pulse along a nanowire target is investigated. In the process of interaction, dense electron bunches are displaced from the target and accelerated in the laser field, generating intense electromagnetic radiation. Three regimes of interaction can be realised depending on the duration and shape of the laser pulse. In the first regime, when the laser pulse is long enough (tens and hundreds of femtoseconds), electrons are only partially forced out of the target. The characteristics of the low-frequency part of the spectrum of the generated radiation are determined in this case by the duration of the laser pulse, as well as by its amplitude and target parameters (geometric dimensions and concentration of electrons). In the second regime, the laser pulse has a large amplitude and a steep rising edge (the amplitude of the first half-wave is of the order of the maximum pulse amplitude); as a result, most of the electrons are displaced from the target already at the initial moment of interaction. In this regime, unipolar and bipolar pulses with a duration of tens of laser field periods can be formed. Changing the target length makes it possible to control the period of field oscillations and their number in the generated radiation. In the intermediate regime of short laser pulses with an insufficiently steep rising edge, oscillations of the formed electron bunches can occur in the macroscopic Coulomb attraction field of the charged target, which gives rise to radiation with a frequency several times lower than that of laser radiation. In this case, the pulses of the generated radiation contain a few cycles of the field with decreasing amplitude and increasing frequency. Using numerical simulation in three regimes of interaction, the characteristics of IR and terahertz radiation are found, in particular, the pulse shapes, ranges of generated frequencies, amplitudes and angular distributions of radiation are determined. It is shown that the amplitude of the generated pulse can reach subrelativistic and relativistic values (the field strength is more than 1 TV m−1 at a frequency ten times lower than the laser radiation frequency), and the energy conversion efficiency can be of the order of one percent.
A coupled human–natural system analysis of freshwater security under climate and population change
Authors: Yoon Jim , Klassert Christian , Selby Philip , Lachaut Thibaut , Knox Stephen , Avisse Nicolas , Harou Julien , Tilmant Amaury , Klauer Bernd , Mustafa Daanish , Sigel Katja , Talozi Samer , Gawel Erik , Medellín-Azuara Josue , Bataineh Bushra , Zhang Hua , Gorelick Steven M. 
Published: March 2021

Significance
Jordan is facing an unfolding water crisis, exacerbated by climate change and conflict-induced refugee influxes. We present a freshwater security analysis for the country, enabled by an integrated systems model that combines simulation of Jordan’s natural and built water environment with thousands of representative human agents determining water allocation and use decisions. Our analysis points to severe, potentially destabilizing, declines in Jordan’s freshwater security. Without intervening measures, over 90% of Jordan’s low-income population will be experiencing critical water insecurity by the end of the century. To gain a foothold on its water future, Jordan must enact an ambitious portfolio of interventions that span supply- and demand-side measures, including large-scale desalinization and comprehensive water-sector reform.
The myosin II coiled-coil domain atomic structure in its native environment
Authors: Rahmani Hamidreza , Ma Wen , Hu Zhongjun , Daneshparvar Nadia , Taylor Dianne W. , McCammon J. Andrew , Irving Thomas C. , Edwards Robert J. , Taylor Kenneth A. 
Published: March 2021

SignificanceMyosin II is the molecule that produces force in muscle contraction. Unlike the myosin head, its molecular motor, no atomic resolution structure of the ∼1000-residue–long α-helical coiled-coil tail has been reported. Here, we describe the cryo-EM atomic structure of the myosin tail within a native muscle thick filament. Three differences with crystal structures of myosin tail segments were found. The myosin head arrangement apparently alters the beginning of the tail. Striated muscle myosins have four skip residues, amino acids inserted to improve the alignment of charged residue clusters. Skips 1 and 3 agree with the crystal structures. Skip 2, which is a novel structure, and Skip 4 do not. Functional consequences are suggested by the myosin tail packing.
Tuning interactions between spins in a superconductor
Authors: Ding Hao , Hu Yuwen , Randeria Mallika T. , Hoffman Silas , Deb Oindrila , Klinovaja Jelena , Loss Daniel , Yazdani Ali 
Published: March 2021

Significance
Majorana zero modes (MZMs) have been proposed as the building blocks for fault-tolerant topological quantum computation. Recent experiments have found both spin and charge signatures of MZMs at the ends of spin chains on superconducting surfaces. However, the properties of such chains have not been reliably controlled experimentally. Here, we present a platform in which long-range spin–spin interactions and hybridization of spin-induced in-gap states on the surface of a superconductor can be tuned with unprecedented precision by changing the distance between the spins using an atomic manipulation technique. This capability is required for tailoring magnetic textures and engineering in-gap states band structures in spin assemblies and opens up the possibility of exploring new topological superconducting phases with tunable properties.
Substrate discrimination and quality control require each catalytic activity of TRAMP and the nuclear RNA exosome
Authors: Das Mom , Zattas Dimitrios , Zinder John C. , Wasmuth Elizabeth V. , Henri Julien , Lima Christopher D. 
Published: March 2021

Significance
Defects in RNA quality control pathways manifest as disease because they function to selectively remove aberrant or defective species to ensure cellular homeostasis. The RNA exosome and TRAMP complexes encompass key components of the RNA surveillance machinery. Here we show that exoribonuclease activities of Rrp6-associated RNA exosomes protect stable RNA species from TRAMP-mediated polyadenylation and degradation, and that each catalytic activity of the RNA exosome-TRAMP complex contributes to substrate discrimination and degradation of less stable RNA species. Our results highlight a previously unappreciated role for Rrp6 in protecting stable RNA species from degradation and suggest additional mechanistic analogies between RNA and protein quality control pathways with respect to proofreading mechanisms that protect stable species while targeting unstable species for destruction.
Exploring nanowire regrowth for the integration of bottom-up grown silicon nanowires into AFM scanning probes
Authors: Behroudj A , Salimitari P , Nilsen M , Strehle S 
Published: March 2021

Abstract
Bottom-up grown single-crystalline silicon nanowires (SiNWs) are highly intriguing to build nanoscale probes, for instance for atomic force microscopy (AFM), due to their mechanical robustness and high aspect ratio geometry. Several strategies to build such nanowire-equipped probes were explored but their fabrication is still elaborate, time-consuming and relies partly on single-crystalline substrates. Here, we explore a new strategy to fabricate AFM probes that are equipped with single-SiNW scanning tips. The conceptual evaluation begins with a discussion on the overall design and softness of such probes based on finite-element-method simulations. For the experimental realization, SiNWs were grown by the well-established gold-catalyzed vapor–liquid–solid method employing gaseous monosilane. As-grown SiNWs were subsequently transferred onto flexible membranes and even freestanding AFM microcantilever beams via mechanical nanowire contact printing. Elongation of the deposited nanowires by so-called regrowth was triggered by reusing the original gold catalyst to yield the prospective AFM scanning tip. SiNW-equipped scanning probes were created in this manner and were successfully employed for topography imaging. Although a multitude of challenges remains, the created probes showed an overall convincing performance and a superior durability.
Influence of ZnO nanorod surface chemistry on passivation effect of TiO2 shell coating
Authors: Li Xuan , Tu Ying , Pace Simona , Anselmi-Tamburini Umberto , Briscoe Joe 
Published: March 2021

Abstract
Core–shell structures with ZnO cores have been widely investigated due to their effectiveness in suppressing surface defects of ZnO nanostructures. As the surface defects are hugely dependent on the synthesis conditions, it is important to understand the interactions between shell material and ZnO with different surface chemistry. Here we produce well-aligned ZnO nanorods using two growth methods, leading to ZnO with different surface chemistries. A thin layer of TiO2 shell is applied via layer-by-layer adsorption method. The core–shell structure is confirmed via high-resolution transmission electron microscopy. The optical properties and chemical states of both bare nanorods and core–shell structures are investigated and compared using photoluminescence (PL) measurement and x-ray photoelectron spectroscopy (XPS). Both PL and XPS results suggest surface defects are passivated by TiO2 shell coating. The shell coating has a stronger effect on ZnO synthesized in OH− rich environment, due to excessive hydroxyl groups provided during synthesis, which remain even after annealing-induced crystallization.
An optimized stacked diagnosis structure for fault diagnosis of wind turbine planetary gearbox
Authors: Lu Li , He Yigang , Ruan Yi , Yuan Weibo 
Published: March 2021

Abstract
Fault diagnosis of the planetary gearbox (PGB) of wind turbines (WTs) plays an important role in the normal operation of WTs. Current studies commonly focus on the diagnosis of fault types of WT PGBs. Nevertheless, in addition to identifying the fault type, the current severity of the fault is also instructive for the maintenance and repair of WT PGBs. Thus, a novel optimized stacked diagnosis structure (OSDS) is proposed for the identification of fault type and severity. Compressed sensing is adopted to implement the compressed sampling of original vibration signals collected by the wireless sensor. Then, the compressed samples are input into first- and second-layer deep belief networks (DBNs) for the separate identification of fault type and severity. In order to realize the best feature extraction performance of DBNs, every single DBN in the OSDS is optimized with the chaotic quantum particle swarm optimization (CQPSO) algorithm. For OSDS, which is a hierarchical diagnosis system, the misdiagnosis results of the first layer will bring irreversible influence to the diagnosis of the second layer. That is to say, an incorrect fault type diagnosis will mean that these signals are wrongly classified, making them unable to judge the severity of the fault. Because the first-layer DBN is optimized with PGB historical data and the CQPSO algorithm, it shows an excellent performance in identifying fault types. Therefore, the diagnostic performance of OSDS has not been affected by the absence of diagnosis, and still shows an excellent recognition performance of fault type and severity in the experiment. This verifies its excellent role in the fault diagnosis of WT PGBs.
Self-assembled polymeric micelles for targeted photodynamic therapy of human epidermal growth factor receptor 2 overexpressing breast cancer
Authors: Kim Young-Jin , Ha Ji-Hui , Kim Ye-Ji 
Published: March 2021

Abstract
Photodynamic therapy (PDT) has been extensively explored as a promising alternative therapeutic approach for many malignant tumors. However, the PDT system generally involves unsatisfactory tumor specificity and nonspecific accumulation of photosensitizers around the target cancer cells, leading to phototoxic damage to adjacent healthy normal cells. In this study, we developed pheophorbide a (Pheo a)/human epidermal growth factor receptor 2 (HER2) targeting peptide (epitope form, HLTV, PEG2-LTVSPWY)-co-conjugated methoxy poly(ethylene glycol)-block-poly(L-lysine hydrochloride) (PEG-PLL)/hyaluronic acid (HA) (P3H2) polymeric micelles via a self-assembly method for HER2-targeted PDT treatment for breast cancer, thereby enhancing the PDT efficacy. The synthesized P3H2 polymeric micelles were spherical, with an average diameter of 125.7 ± 21.2 nm in an aqueous solution. The results of in vitro cytotoxicity assays demonstrated that the P3H2 polymeric micelles significantly improved PDT efficacy on the SK-BR-3 cells due to the enhanced targeting ability. In addition, PDT treatment using the P3H2 polymeric micelles effectively killed breast cancer cells by inducing higher intracellular reactive oxygen species generation and apoptotic cell death. In particular, the three-dimensional cell culture model proved the synergistic PDT efficacy using P3H2 polymeric micelles on the SK-BR-3 cells. Based on these results, the PDT treatment using P3H2 polymeric micelles can serve as a highly effective therapeutic modality for breast cancer.
Insight into the capacity decay mechanism of cycled LiNi0.5Co0.2Mn0.3O2 cathodes via in situ x-ray diffraction
Authors: Huang Yalan , Zhu He , Zhu Hekang , Zhang Jian , Ren Yang , Liu Qi 
Published: March 2021

Abstract
Layered LiNi
x
Co
y
Mn1-x-y
O2 (NCM) is expected to dominate the future cathode technology of the automotive industry, due to its high energy density and low cost. Despite its excellent prospects, however, the severe capacity decay of NCM cathodes has prevented this promising material from achieving further success. The mechanism underlying this phenomenon is controversial and has been generally understood as arising from the complex structural changes that take place upon Li-(de)intercalation. However, deeper insight has not been available due to unclear structural kinetics, in particular, in cycled NCM cathodes. For this study, we conducted in situ high-energy synchrotron x-ray diffraction (XRD) measurements on a typical LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode that had been operated for 90 cycles, then compared the results with those collected from a fresh NCM532 electrode. It was revealed that the H1–H2 phase transition that only occurs at the first cycle is irreversible. Remarkably, the c-contraction triggered by the H2-H3 transition, which is expected to be the major cause of intergranular cracks in electrodes, became even more profound after cycling. Combining the above results with electrochemical testing and microscopic imaging, we discuss the interplay between structural dynamics and performance degradation in NCM532 in detail. This study provides key evidence for a mechanically induced capacity decay mechanism, which is expected to be extended to NCM materials with various compositions.
Ultrahigh dose-rate (FLASH) x-ray irradiator for pre-clinical laboratory research
Authors: Rezaee Mohammad , Iordachita Iulian , Wong John W 
Published: March 2021

Abstract
FLASH irradiation has been shown to reduce significantly normal tissue toxicity compared to conventional irradiation, while maintaining tumor control probability at similar level. Clinical translation of FLASH irradiation necessitates comprehensive laboratory studies to elucidate biological effects as well as pertinent technological and physical requirements. At present, FLASH research employs complex accelerator technologies of limited accessibilities. Here, we study the feasibility of a novel self-shielded x-ray irradiation cabinet system, as an enabling technology to enhance the preclinical research capabilities. The proposed system employs two commercially available high capacity 150 kVp fluoroscopy x-ray sources with rotating anode technology in a parallel-opposed arrangement. Simulation was performed with the GEANT4 Monte-Carlo platform. Simulated dosimetric properties of the x-ray beam for both FLASH and conventional dose-rate irradiations were characterized. Dose and dose rate from a single kV x-ray fluoroscopy source in solid water phantom were verified with measurements using Gafchromic films. The parallel-opposed x-ray sources can deliver over 50 Gy doses to a 20 mm thick water equivalent medium at ultrahigh dose-rates of 40–240 Gy s−1. A uniform depth-dose rate (±5%) is achieved over 8–12 mm in the central region of the phantom. Mirrored beams minimize heel effect of the source and achieve reasonable cross-beam uniformity (±3%). Conventional dose-rate irradiation (≤0.1 Gy s−1) can also be achieved by reducing the tube current and increasing the distance between the phantom and tubes. The rotating anode x-ray source can be used to deliver both FLASH and conventional dose-rate irradiations with the field dimensions well suitable for small animal and cell-culture irradiations. For FLASH irradiation using parallel-opposed sources, entrance and exit doses can be higher by 30% than the dose at the phantom center. Beam angling can be employed to minimize the high surface doses. Our proposed system is amendable to self-shielding and enhance research in regular laboratory setting.
Recent progress on neoclassical impurity transport in stellarators with implications for a stellarator reactor
Authors: Buller S , Smith H M , Mollén A 
Published: March 2021

Abstract
Accumulation of impurities in the core of the plasma is a potential problem for any fusion reactor, and is thought to be especially problematic for stellarators. We use the collisional transport code Sfincs to calculate, in a reactor stellarator scenario, the effects of flux-surface electrostatic potential variation on tungsten transport. The potential variation is found to have a large effect on the transport, reversing the sign of the transport coefficients related to the radial electric field and the bulk ion temperature gradient, and also increasing the magnitude of the former by two orders of magnitude. We optimize the electrostatic potential variation to minimize impurity accumulation, resulting in a 20%–50% reduction of the inward impurity flux. Furthermore, we investigate whether the electrostatic potential variation caused by fast particles due to ion-cyclotron resonance heating can be used to reduce the impurity accumulation, but find the effect to be small in the cases considered.
Implications of current nuclear cross sections on secondary cosmic rays with the upcoming DRAGON2 code
Authors: De La Torre Luque P. , Mazziotta M.N. , Loparco F. , Gargano F. , Serini D. 
Published: March 2021

Abstract
Current measurements of cosmic-ray fluxes have reached
unprecedented accuracy thanks to the new generation of experiments,
and in particular the AMS-02 mission. At the same time, significant
progress has been made in the propagation models of galactic cosmic
rays. These models include several propagation parameters, which are
usually inferred from the ratios of secondary to primary cosmic
rays, and which depend on the cross sections describing the
collisions among the various species of cosmic-ray nuclei. At
present, our knowledge of these cross sections in the energy range
where cosmic-ray interactions occur is limited, and this is a source
of uncertainties in the predicted fluxes of secondary cosmic-ray
nuclei. In this work we study the impact of the cross section
uncertainties on the fluxes of light secondary nuclei (Li, Be, B)
using a preliminary version of the upcoming DRAGON2 code. We
first present a detailed comparison of the secondary fluxes computed
by implementing different parameterizations for the network of
spallation cross sections. Then, we discuss the use of
secondary-over-secondary cosmic-ray flux ratios as a tool to improve
the consistency of cross sections parameterizations and give insight
of the overall uncertainties coming from the cross sections
parametrisations. We show that the uncertainties inferred from the
cross section data are enough to explain the discrepancies in the Be
and Li fluxes with respect to the AMS-02 data, with no need of a
primary component in their spectra. In addition, we show that the
fluxes of B, Be and Li can be simultaneously reproduced by rescaling
their cross sections within the experimental uncertainty. Finally,
we also revisit the diffusive estimation of the halo size, obtaining
good agreement with previous works and a best fit value of
6.8 ± 1 kpc from the most updated cross sections
parametrisations.
A mathematical model of Zika disease by considering transition from the asymptomatic to symptomatic phase
Authors: Aldila D , Rasyiqah K , Ardaneswari G , Tasman H. 
Published: March 2021

Abstract
This work presents a mathematical model of Zika disease considering infected individual transition from the asymptomatic to symptomatic phase. Zika virus (ZIKV) itself is a virus that belongs to arbovirus transmitted by the Aedes aegypti mosquitoes. It can also be transmitted through human contact such as sexual contact, blood transfussion, and transplacental infection. As a matter of fact, 80% of those who get infected by ZIKV are asymptomatic. In this work, we investigate the Zika model by considering individual transition case from the asymptomatic to symptomatic phase using SEAIR (host) - SI (vector) model. In this model, we involve human and mosquito populations which have a big role to the transmission of ZIKV itself. In this study, basic reproduction number (R
0) calculated as the largest eigenvalue of Next-Generation Matrix. Furthermore, analytical results also be conducted to determine the existence and local stability of the equilibrium point. A numerical simulation presented to analyze the sensitivity and elasticity of R
0 for some parameters involved in the model, and followed with simulation of autonomous system. We find that transition of asymptomatic to symptomatic case in Zika transmission hold an important role in determining the size of the basic reproduction number. More transition to symptomatic case are better to know the “dark” figure of the real cases in the field.
Cluster based area yield scheme for crop insurance policy in Java
Authors: Haryastuti R , Aidi M N , Pasaribu S M , Sumertajaya I M , Sutomo V A , Kusumaningrum D , Anisa R 
Published: March 2021

Abstract
Zone based area yield scheme becomes a potential in improving the development of area yield index for crop insurance policy in Indonesia. The characteristics of productivity varies among municipalities in Indonesia. Therefore, it will be challenging to apply area yield index policy without developing clusters, especially in Java which is considered as one of the central productivities of paddy in Indonesia. Clustering the productivity is one of the solutions to reduce the heterogeneous basis risk within municipalities of a province. Clustering areas is recommended in order to determine accurate critical yield index leading to a more precise ratemaking in the process of developing area yield index policy. In order to define the clusters, we have not only considered average and volatility of productivity over the past ten years, but also integrated the spatial effect of municipalities. Ward-like hierarchical method shows that clustering of municipalities within each province provides better homogeneity. It has been found that there are 12 clusters in Java tend to have low (8.33%), middle (50%), and high (41.67%) productivity. Therefore, we suggest that the Ministry of Agriculture design the area yield index policy based on these clusters and each cluster will have different critical productivity index and adjusted premium.