bluuebunny/crossref_metadata_2025_split huggingface dataset:
Black Carbon Particles Do Not Matter for Immersion Mode Ice Nucleation
Authors: Kanji Zamin A. , Welti André , Corbin Joel C. , Mensah Amewu A. 
Published: May 2020

AbstractThe role of black carbon (BC) in ice crystal formation via immersion freezing relevant for mixed‐phase cloud formation is uncertain. Previous studies report either negligible or significant contributions of BC particles to cloud glaciation via immersion freezing. Despite conflicting evidence, immersion freezing by BC particles is included in several cloud models. Here we show that fossil fuel soot and commercially available hydrocarbon BC is inactive as immersion freezing nuclei for atmospherically relevant particle sizes and surface areas. Instead, temperatures <235 K are necessary for freezing droplets with immersed soot particles, implying homogeneous freezing, rather than immersion freezing by soot. A comparison of the results to previous studies using larger soot aggregates and dust reveals the ineffectiveness of soot as immersion ice nucleating particles. We conclude that soot particles with properties like those investigated here can be neglected for simulating ice nucleation in mixed‐phase clouds.
Broadband VHF Observations of Two Natural Positive Cloud‐to‐Ground Lightning Flashes
Authors: Li Shulei , Qiu Shi , Shi Lihua , Li Yun 
Published: May 2020

AbstractThe characteristics of two natural positive cloud‐to‐ground flashes are analyzed in detail with the broadband very high frequency (VHF) mapping system. The bidirectional leader processes at the lightning initiation are observed, with negative leaders propagating upward and positive leaders propagating downward. The downward positive leaders can be divided into two stages, with scattered and slowly extending sources in the first stage and more concentrated and faster sources in the second stage. The overall extension speeds of the first stages are 1.8 × 104 and 2.7 × 104 m/s for the two flashes, and the speeds of the second stages are 7.8 × 105 and 1.0 × 106 m/s, respectively. The received peak power of the positive leaders is substantially lower than that for the negative leaders. The frequency characteristics show that the second stage emits more high‐frequency radiation than the first stage, while there is no significant difference in low‐frequency radiation content.
Convective Erosion of a Primordial Stratification Atop Earth's Core
Authors: Bouffard M. , Landeau M. , Goument A. 
Published: May 2020

AbstractSeismic and geomagnetic observations suggest the presence of a stratified layer atop Earth's core. Previous laboratory experiments showed that this layer could be primordial, produced by a collision between the primitive Earth and a giant impactor. However, paleomagnetic data require turbulent flow motions in the core for the last 3.4 Ga. Such flows can erode an existing stratification. It is therefore unclear whether a primordial stratification still exists nowadays. Here, we use numerical simulations to investigate the erosion by thermal convection of a chemical layer atop Earth's core. Our scaling law predicts that a primordial layer thicker than 1 km with a density anomaly above 0.01% can survive 4.5 Ga of convective erosion. We conclude that the observed present‐day stratification could be a vestige of core formation. We also observe strong double‐diffusive flows in the layer. These might reconcile the existence of a stratification with the present‐day structure of the geomagnetic field.
Decreasing Landslide Erosion on Steeper Slopes in Soil‐Mantled Landscapes
Authors: Prancevic Jeff P. , Lamb Michael P. , McArdell Brian W. , Rickli Christian , Kirchner James W. 
Published: May 2020

AbstractSlope‐stability models predict that steeper hillslopes require smaller hydrological triggers for shallow landslides to occur due to the added downslope pull of gravity, which should result in more frequent landslides and faster erosion. However, field observations indicate that landslide frequency does not consistently increase on steeper hillslopes. Here, we use measurements of 1,096 soil landslides in California and Switzerland, and a compilation of landslide geometries, to show that steeper hillslopes typically have thinner soils and that thin soils inhibit landslides due to enhanced roles of cohesion and boundary stresses. We find that the landscape‐averaged landslide erosion depth peaks near the threshold slope for instability, and it drops to half that value on hillslopes that are just 5° to 10° steeper. We propose that faster rates of soil creep on steeper slopes cause thin and more stable soils, which in turn reduces landslide erosion, despite the added pull of gravity.
Excitation of Whistler Waves Through the Bidirectional Field‐Aligned Electron Beams With Electron Temperature Anisotropy: MMS Observations
Authors: Huang S. Y. , Xu S. B. , He L. H. , Jiang K. , Yuan Z. G. , Deng X. H. , Wei Y. Y. , Zhang J. , Zhang Z. H. 
Published: May 2020

AbstractUsing four‐point measurements from the Magnetospheric Multiscale (MMS) mission, we identify whistler waves at the boundary of an ion scale magnetic hole, which should be locally excited rather than propagated from other regions. Based on the measured local plasma parameters, which include those for bidirectional electron beams with electron temperature anisotropy, the frequency range with the growth rate derived from kinetic theory is consistent with the observations, while the growth rate in the absence of such beams is negative; hence, the observed whistler waves are locally excited by the bidirectional electron beams with electron temperature anisotropy. The dispersion relation, derived from one‐dimensional particle‐in‐cell simulations that are conducted using the inputs of the bidirectional electron beams with electron temperature anisotropy, agrees well with the one from kinetic theory, which further supports this excitation mechanism. Our results shed light on a new excitation mechanism for whistler waves.
Force microscopy of the Caenorhabditis elegans embryonic eggshell
Authors: Krenger Roger , Burri Jan T. , Lehnert Thomas , Nelson Bradley J. , Gijs Martin A. M. 
Published: May 2020

AbstractAssays focusing on emerging biological phenomena in an animal’s life can be performed during embryogenesis. While the embryo of Caenorhabditis elegans has been extensively studied, its biomechanical properties are largely unknown. Here, we demonstrate that cellular force microscopy (CFM), a recently developed technique that combines micro-indentation with high resolution force sensing approaching that of atomic force microscopy, can be successfully applied to C. elegans embryos. We performed, for the first time, a quantitative study of the mechanical properties of the eggshell of living C. elegans embryos and demonstrate the capability of the system to detect alterations of its mechanical parameters and shell defects upon chemical treatments. In addition to investigating natural eggshells, we applied different eggshell treatments, i.e., exposure to sodium hypochlorite and chitinase solutions, respectively, that selectively modified the multilayer eggshell structure, in order to evaluate the impact of the different layers on the mechanical integrity of the embryo. Finite element method simulations based on a simple embryo model were used to extract characteristic eggshell parameters from the experimental micro-indentation force-displacement curves. We found a strong correlation between the severity of the chemical treatment and the rigidity of the shell. Furthermore, our results showed, in contrast to previous assumptions, that short bleach treatments not only selectively remove the outermost vitelline layer of the eggshell, but also significantly degenerate the underlying chitin layer, which is primarily responsible for the mechanical stability of the egg.
Hierarchical highly ordered SnO2 nanobowl branched ZnO nanowires for ultrasensitive and selective hydrogen sulfide gas sensing
Authors: Zhu Li-Yuan , Yuan Kai-Ping , Yang Jia-He , Hang Cheng-Zhou , Ma Hong-Ping , Ji Xin-Ming , Devi Anjana , Lu Hong-Liang , Zhang David Wei 
Published: May 2020

AbstractHighly sensitive and selective hydrogen sulfide (H2S) sensors based on hierarchical highly ordered SnO2 nanobowl branched ZnO nanowires (NWs) were synthesized via a sequential process combining hard template processing, atomic-layer deposition, and hydrothermal processing. The hierarchical sensing materials were prepared in situ on microelectromechanical systems, which are expected to achieve high-performance gas sensors with superior sensitivity, long-term stability and repeatability, as well as low power consumption. Specifically, the hierarchical nanobowl SnO2@ZnO NW sensor displayed a high sensitivity of 6.24, a fast response and recovery speed (i.e., 14 s and 39 s, respectively), and an excellent selectivity when detecting 1 ppm H2S at 250 °C, whose rate of resistance change (i.e., 5.24) is 2.6 times higher than that of the pristine SnO2 nanobowl sensor. The improved sensing performance could be attributed to the increased specific surface area, the formation of heterojunctions and homojunctions, as well as the additional reaction between ZnO and H2S, which were confirmed by electrochemical characterization and band alignment analysis. Moreover, the well-structured hierarchical sensors maintained stable performance after a month, suggesting excellent stability and repeatability. In summary, such well-designed hierarchical highly ordered nanobowl SnO2@ZnO NW gas sensors demonstrate favorable potential for enhanced sensitive and selective H2S detection with long-term stability and repeatability.
“Top-down” and “bottom-up” strategies for wafer-scaled miniaturized gas sensors design and fabrication
Authors: Liu Lin , Wang Yingyi , Sun Fuqin , Dai Yanbing , Wang Shuqi , Bai Yuanyuan , Li Lianhui , Li Tie , Zhang Ting , Qin Sujie 
Published: May 2020

AbstractManufacture of large-scale patterned nanomaterials via top-down techniques, such as printing and slurry coating, have been used for fabrication of miniaturized gas sensors. However, the reproducibility and uniformity of the sensors in wafer-scale fabrication are still a challenge. In this work, a “top-down” and “bottom-up” combined strategy was proposed to manufacture wafer-scaled miniaturized gas sensors with high-throughput by in-situ growth of Ni(OH)2 nanowalls at specific locations. First, the micro-hotplate based sensor chips were fabricated on a two-inch (2”) silicon wafer by micro-electro-mechanical-system (MEMS) fabrication techniques (“top-down” strategy). Then a template-guided controllable de-wetting method was used to assemble a porous thermoplastic elastomer (TPE) thin film with uniform micro-sized holes (relative standard deviation (RSD) of the size of micro-holes <3.5 %, n > 300), which serves as the patterned mask for in-situ growing Ni(OH)2 nanowalls at the micro-hole areas (“bottom-up” strategy). The obtained gas microsensors based on this strategy showed great reproducibility of electric properties (RSD < 0.8%, n = 8) and sensing response toward real-time H2S detection (RSD < 3.5%, n = 8).
Increases in arm volume predict lymphoedema and quality of life deficits after axillary surgery: a prospective cohort study
Authors:   the Investigators of BEA/PLACE studies, Bundred Nigel , Foden Phil , Todd Chris , Morris Julie , Watterson Donna , Purushotham Arnie , Bramley Maria , Riches Katie , Hodgkiss Tracey , Evans Abigail , Skene Anthony , Keeley Vaughan 
Published: May 2020

Abstract
Background
Lymphoedema develops after axillary clearance (ANC) in 25% of patients. This prospective, multi-centre study compared multi-frequency bioimpedance spectroscopy (BIS) with arm volume measurement to: (1) determine which test has better diagnostic accuracy, (2) identify factors predicting development of lymphoedema, and its effect on quality-of-life.

Methods
Participants (N = 1100) underwent measurements pre and post-ANC surgery for breast cancer. Relative arm volume increase (RAVI) of >10% diagnosed lymphoedema. Predictors of lymphoedema were determined using logistic regression. Optimal diagnostic method was assessed using diagnostic accuracy. Quality-of-life was assessed using the FACT B + 4 questionnaire.

Results
Lymphoedema was diagnosed in 22.8% women using RAVI > 10%, 45.6% using BIS criteria, while 24.5% underwent compression sleeve application by 24 months. BMI > 30 was an independent factor for both development (p = 0.005) and progression (p = 0.015) of lymphoedema. RAVI at 1 month, BMI > 30 and number of involved nodes contributed to a novel scoring model to predict lymphoedema by 36 months. Larger decreases in QoL scores post-surgery occurred in lymphoedema patients (p < 0.001). Progression to moderate lymphoedema occurred in 15% patients after sleeve application.

Conclusions
RAVI measurement was the best diagnostic tool for lymphoedema. BIS alone is not appropriate for lymphoedema screening or diagnosis. BMI > 30 predicted lymphoedema diagnosis and progression.
Tumour budding and tumour–stroma ratio in hepatocellular carcinoma
Authors: Kairaluoma Valtteri , Kemi Niko , Pohjanen Vesa-Matti , Saarnio Juha , Helminen Olli 
Published: May 2020

Abstract
Background
Tumour budding and low tumour–stroma ratio (TSR) are associated with poor prognosis in some cancers, but their value in Western hepatocellular carcinoma is unclear. The prognostic value of tumour budding and TSR in hepatocellular carcinoma was examined.

Methods
Some 259 hepatocellular carcinoma patients treated in Oulu University Hospital 1983–2018 were included in this retrospective cohort study. Tumour budding and TSR were analysed from the haematoxylin- and eosin-stained original diagnostic slides, by dividing patients into bud-negative (0 bud) or bud-positive (≥1 bud) groups, and into high TSR (<50%) and low TSR (≥50%) groups. Surgically treated patients (n = 47) and other treatments (n = 212) were analysed separately. Primary outcomes were overall, and disease-specific 5-year mortality was adjusted for confounding factors.

Results
Surgically treated patients with positive tumour budding had increased 5-year overall (adjusted HR 3.87, 95% CI 1.10–13.61) and disease-specific (adjusted HR 6.17, 95% CI 1.19–31.90) mortality compared with bud-negative patients. In surgically treated patients, TSR had no effect on 5-year overall (adjusted HR 2.03, 95% CI 0.57–7.21) or disease-specific (adjusted HR 3.23, 95% CI 0.78–13.37) mortality. No difference in survival related to tumour budding and TSR in non-surgically treated patients was observed.

Conclusions
Tumour budding is a prognostic factor in surgically treated hepatocellular carcinoma.
Effects of effective stereotactic radiosurgery for brain metastases on the adjacent brain parenchyma
Authors: Wagner Sabine , Lanfermann Heinrich , Wohlgemuth Walter Alexander , Gufler Hubert 
Published: May 2020

Abstract
Background
To evaluate whether functional and metabolic MRI can detect radiation-induced alterations in the adjacent areas after effective stereotactic radiosurgery (SRS) for brain metastases. If confirmed, these techniques may be suited for monitoring the timely stratification of patients for neuroprotective treatments after irradiation.

Methods
Inclusion criteria were complete response, partial response, or stable disease on routine follow-up MR-scans. Multiparametric 3T-MRI was performed with diffusion-weighted imaging, dynamic susceptibility perfusion-weighted imaging, and two-dimensional proton MR-spectroscopy. Parameters were measured in the SRS-treated target and in the adjacent parenchyma up to both 0.75 cm and 1.5 cm from the target border.

Results
Nineteen lesions in sixteen consecutive patients met the inclusion criteria. The median follow-up time was 39 months (range, 10–142) with 41 multiparametric MR-examinations in total. We found low values of N-acetyl-aspartate up to 1.5 cm from the target borders of SRS (P = 0.043) associated with high values of choline (P = 0.004) at the end of the observation period. Lactate levels in the adjacent tissue declined over time, whereas continuously high apparent-diffusion-coefficient values were noted (P < 0.001).

Conclusion
Multiparametric MRI can depict radiobiological effects and their time course at a distance from the effectively treated site after SRS for brain metastases, even if conventional MRI findings are inconspicuous.
Polaron Diffusion in Pentathienoacene Crystals
Authors: Pereira Marcelo Lopes , Sousa Rafael Timóteo , Giozza William Ferreira , Ribeiro Luiz Antonio 
Published: May 2020

AbstractMolecular crystals have been used as prototypes for studying the energetic and dynamic properties of charge carriers in organic electronics. The growing interest in oligoacenes and fused-ring oligothiophenes in the last two decades is due, in particular, to the success achieved in conceiving pentacene-based organic photovoltaic devices. In the present work, a one-dimensional Holstein-Peierls model is designed to study the temperature-dependent polaron transport in pentathienoacene (PTA) lattices. The tight-binding Hamiltonian employed here takes into account intra and intermolecular electron-lattice interactions. Results reveal that polarons in PTAs can be stable structures even at high temperatures, about 400 K. During the dynamical process, these charge carriers present a typical 1D random walk diffusive motion with a low activation energy of 13 meV and a room temperature diffusivity constant of 1.07 × 10−3 cm2 s−1. Importantly, these critical values for the polaron diffusion and activation energy are related to the choice of model parameters, which are adopted to describe pristine lattices.
Contactless mass transfer for intra-droplet extraction
Authors: Asano Shusaku , Takahashi Yu , Maki Taisuke , Muranaka Yosuke , Cherkasov Nikolay , Mae Kazuhiro 
Published: May 2020

AbstractThis study demonstrates the possibility of “contactless” mass transfer between two aqueous slugs (droplets) separated by an oil slug in Taylor flow inside milli-channels. Separation of the alternating aqueous slugs at the outlet was performed by switching a couple of solenoid valves at branched outlets according to signals obtained by an optical sensor at the branch. Transfer of bromothymol blue (BTB) from acidic to basic aqueous slugs was performed for demonstration. In some cases, aqueous slugs separated by oil, merged catching on each other due to the velocity difference. Interfacial tension which was affected by the solute concentration was responsible for the velocity difference. Position-specific mass transfer activity at the rear end of the aqueous slugs was found on the course of the experiment. A meandering channel decreased the velocity difference and enhanced mass transfer. Almost complete (93%) transfer of BTB was achieved within a short residence time of several minutes under optimized conditions. The presented system opens a way for advanced separation using minimum amounts of the oil phase and allows concentrating the solute by altering relative lengths of the sender and receiver slugs.
lncRNA AFAP1-AS1 promotes triple negative breast cancer cell proliferation and invasion via targeting miR-145 to regulate MTH1 expression
Authors: Zhang Xiaohui , Zhou Yidong , Mao Feng , Lin Yan , Shen Songjie , Sun Qiang 
Published: May 2020

AbstractThe actin fiber-associated protein 1-antisense RNA1 (AFAP1-AS1) is upregulated in various cancers and associated with cancer proliferation and metastasis. Several cancer-related pathways have been linked to up-expression of this long non-coding (lnc)RNA, but the underlying mechanisms are yet unknown. In triple negative breast cancer (TNBC), AFAP1-AS1 expression is also significantly overexpressed compared to that in other subtypes of breast cancer from the TCGA dataset. In this study, we performed bioinformatic RNAhybrid analyses and identified that miR-145 is a potential target of AFAP1-AS1 and able to reduce MutT homolog-1 (MTH1) expression. Thus, this study investigated the oncogenic activity of AFAP1-AS1 in TNBC cells and the underlying mechanisms that are yet poorly understood. The results showed that miR-145 expression was low, whereas AFAP1-AS1 and MTH1 expression was high in TNBC cells and that miR-145 mimics reduced TNBC cell proliferation and invasion, whereas miR-145 knockdown exerted the opposite activity in TNBC cells. Moreover, knockdown of AFAP1-AS1 reduced tumor cell proliferation and invasion, but miR-145 co-transfection rescued tumor cell viability and colony formation ability. The dual luciferase reporter assay showed that AFAP1-AS1 could directly target miR-145, while miR-145 could directly target MTH1. After knockdown of ATF6, AFAP1-AS1 was reduced along with AFAP1-AS1 promoter activity. This study revealed that AFAP1-AS1 could promote TNBC cell proliferation and invasion via regulation of MTH1 expression through targeting of miR-145.
Detecting cortical circuits resonant to high-frequency oscillations in the human primary motor cortex: a TMS-tACS study
Authors: Guerra Andrea , Ranieri Federico , Falato Emma , Musumeci Gabriella , Di Santo Alessandro , Asci Francesco , Di Pino Giovanni , Suppa Antonio , Berardelli Alfredo , Di Lazzaro Vincenzo 
Published: May 2020

AbstractCorticospinal volleys evoked by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1) consist of high-frequency bursts (≈667 and ≈333 Hz). However, intracortical circuits producing such corticospinal high-frequency bursts are unknown. We here investigated whether neurons activated by single TMS pulses over M1 are resonant to high-frequency oscillations, using a combined transcranial alternating current stimulation (tACS)-TMS approach. We applied 667, 333 Hz or sham-tACS and, concurrently, we delivered six single-pulse TMS protocols using monophasic or biphasic pulses, different stimulation intensities, muscular states, types and orientations of coils. We recorded motor evoked potentials (MEPs) before, during and after tACS. 333 Hz tACS facilitated MEPs evoked by biphasic TMS through a figure-of-eight coil at active motor threshold (AMT), and by monophasic TMS with anterior-to-posterior-induced current in the brain. 333 Hz tACS also facilitated MEPs evoked by monophasic TMS through a circular coil at AMT, an effect that weakly persisted after the stimulation. 667 Hz tACS had no effects. 333 Hz, but not 667 Hz, tACS may have reinforced the synchronization of specific neurons to high-frequency oscillations enhancing this activity, and facilitating MEPs. Our findings suggest that different bursting modes of corticospinal neurons are produced by separate circuits with different oscillatory properties.