bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-Omics Analysis of Primary Cell Culture Models Reveals Genetic and Epigenetic Basis of Intratumoral Phenotypic Diversity
Authors: Liu Sixue , Yang Zuyu , Li Guanghao , Li Chunyan , Luo Yanting , Gong Qiang , Wu Xin , Li Tao , Zhang Zhiqian , Xing Baocai , Xu Xiaolan , Lu Xuemei 
Published: March 2020

Abstract
Uncovering the functionally essential variations related to tumorigenesis and tumor progression from cancer genomics data is still challenging due to the genetic diversity among patients, and extensive inter- and intra-tumoral heterogeneity at different levels of gene expression regulation, including but not limited to the genomic, epigenomic, and transcriptional levels. To minimize the impact of germline genetic heterogeneities, in this study, we establish multiple primary cultures from the primary and recurrent tumors of a single patient with hepatocellular carcinoma (HCC). Multi-omics sequencing was performed for these cultures that encompass the diversity of tumor cells from the same patient. Variations in the genome sequence, epigenetic modification, and gene expression are used to infer the phylogenetic relationships of these cell cultures. We find the discrepancy among the relationships revealed by single nucleotide variations (SNVs) and transcriptional/epigenomic profiles from the cell cultures. We fail to find overlap between sample-specific mutated genes and differentially expressed genes (DEGs), suggesting that most of the heterogeneous SNVs among tumor stages or lineages of the patient are functionally insignificant. Moreover, copy number alterations (CNAs) and DNA methylation variation within gene bodies, rather than promoters, are significantly correlated with gene expression variability among these cell cultures. Pathway analysis of CNA/DNA methylation-related genes indicates that a single cell clone from the recurrent tumor exhibits distinct cellular characteristics and tumorigenicity, and such an observation is further confirmed by cellular experiments both in vitro and in vivo. Our systematic analysis reveals that CNAs and epigenomic changes, rather than SNVs, are more likely to contribute to the phenotypic diversity among subpopulations in the tumor. These findings suggest that new therapeutic strategies targeting gene dosage and epigenetic modification should be considered in personalized cancer medicine. This culture model may be applied to the further identification of plausible determinants of cancer metastasis and relapse.
Hypertension and Acute Mountain Sickness in Himalayan Trekkers in Nepal: An Observational Cohort Study
Authors: Duke Charles B. , Sallade T. Douglas , Starling Jennifer , Pant Sushil , Sheets Alison , McElwee Matthew K. , Young David S. , Taylor Richard Andrew , Keyes Linda E. 
Published: March 2020

Introduction A history of preexisting hypertension is common in people participating in mountain activities; however, the relationship between blood pressure (BP), preexisting hypertension, and acute mountain sickness (AMS) is not well studied. We sought to determine these relationships among trekkers in the Everest region of Nepal. Methods This was a prospective observational cohort study of a convenience sample of adult, nonpregnant volunteers trekking in the Everest Base Camp region in Nepal. We recorded Lake Louise Scores for AMS and measured BP at 2860 m, 3400 m, and 4300 m. The primary outcome was AMS. Results A total of 672 trekkers (including 60 with history of preexisting hypertension) were enrolled at 2860 m. We retained 529 at 3400 m and 363 at 4300 m. At 3400 m, 11% of participants had AMS, and 13% had AMS at 4300 m. We found no relationship between AMS and measured BP values ( P>0.05), nor was there any relation of BP to AMS severity as measured by higher Lake Louise Scores ( P>0.05). Preexisting hypertension (odds ratio [OR] 0.16; 95% CI 0.025–0.57), male sex (OR 0.59; 95% CI 0.37–0.96), and increased SpO2 (OR 0.93; 95% CI 0.87–0.98) were associated with reduced rates of AMS in multivariate analyses adjusting for known risk factors for AMS. Conclusions AMS is common in trekkers in Nepal, even at 3400 m. There is no relationship between measured BP and AMS. However, a medical history of hypertension may be associated with a lower risk of AMS. More work is needed to confirm this novel finding.
Improving Convective Precipitation Forecasts Using Ensemble‐Based Background Error Covariance in 3DVAR Radar Assimilation System
Authors: Thiruvengadam P. , Indu J. , Ghosh Subimal 
Published: March 2020

AbstractSkillful quantitative precipitation forecast using the numerical weather prediction model relies on an accurate estimate of the atmospheric state as an initial condition. Variational assimilation methods (VAR) have the potential to provide improved initial state estimation to the numerical weather prediction model using observations, prior data (background), and their respective error covariance. The quality of variational assimilation hinges on the background error statistics (BES) as it weights the error in prior state and determines the spread of assimilated observations in model space. Traditional approaches used to model stationary BES in a three‐dimensional variational assimilation system often fail to represent the model error in BES. In this study, we have proposed an ensemble method using Stochastically Perturbed Parameterization Tendency to represent the model error in BES. The characteristics of the proposed BES are compared with the traditional approaches using the National Meteorological Centre method for different control variables choices. We have further tested the performance of the proposed method in improving the skill of precipitation forecast for an extreme rainfall event, which caused devastating flood over Chennai city, India, on December 2015. Results demonstrate that the use of the proposed method results in better forecast skill of convective precipitation in terms of both position and intensity than traditional National Meteorological Centre‐based BES. Best results are obtained when zonal and meridional momentum control variables are used for modeling ensemble‐based BES.
Integration of GPS and InSAR Data for Resolving 3‐Dimensional Crustal Deformation
Authors: Shen Zheng‐Kang , Liu Zhen 
Published: March 2020

AbstractWe develop an algorithm to integrate GPS and InSAR data for a 3‐dimensional crustal deformation field at the Earth's surface. In the algorithm discrete GPS data points are interpolated to obtain a 3‐dimensional continuous velocity field, which is then combined with the InSAR line‐of‐sight (LOS) velocity data pixel by pixel using the least‐squares method. Advantages of our method over previous ones are that: 1) The GPS data points are optimally interpolated by balancing a trade‐off between spatial resolution and solution stability. 2) A new algorithm is developed to estimate realistic uncertainties for the interpolated GPS velocities, to be used as weights for GPS data in GPS‐InSAR combination. 3) Realistic uncertainties for the InSAR LOS rate data are estimated and used as weights for InSAR data in GPS‐InSAR combination. 4) The ramps and/or offsets of the InSAR data are globally estimated for all the images to minimize data misfit, particularly at regions where the data overlaps. Application of this method to real data from southern California shows its capability of successfully restoring 3‐dimensional continuous deformation field from spatially limited GPS and dimensionally limited InSAR data. The deformation field reveals water withdrawal induced subsidence and drought caused uplift at various regions in southern California.
Solar Rotational Oscillation and Its Subharmonics in Solar Wind Plasma Field, Geomagnetic, and Cosmic Ray Intensity Indicator in the Solar Cycle 24/25 Minimum
Authors: Singh Y. P. 
Published: March 2020

AbstractTo study synodic period and its subharmonics, we have utilized hourly average data of solar wind plasma field, geomagnetic index, and galactic cosmic ray intensity along with 5 min average data of selected solar wind field parameters during the recent minimum of Solar Cycle 24. Wavelet analyses of hourly average data reveal 28.1, 13.1, and 6.8 day of sigma in interplanetary magnetic field; 27.1, 13.1, and 9.0 day of plasma speed; 27.1, 13.6, 3.9, and 2.2 day of interplanetary electric field; 27.1, 13.6, 3.8, and 2.2 day of southward component of magnetic field; 26.2, 13.6, 8.6, and 3.0 day of geomagnetic Ap index; and 28.1, 11.0, 9.3, 7.0, and 1.6 day periods of galactic cosmic ray intensity. In addition to these prominent short‐term periods, we have significantly observed 6.6, 3.3, and 1.7 day periods of sigma in interplanetary magnetic field (σB); 5.6, 4.2, and 2.2 day of electric field (Ey) and 5.6, 3.3, and 2.4 day of southward component of magnetic field (Bz) in the 5 min average data. During the recent solar minimum, we have observed one solar rotational period and its second, third, fourth, fifth, sixth, seventh, eighth, tenth, eleventh, and twelfth subharmonics. The observed subharmonics of solar rotational period make the current solar minimum very special and noteworthy to study.
Assessing Convective Organization in Tropical Radar Observations
Authors: Retsch M. H. , Jakob C. , Singh M. S. 
Published: March 2020

AbstractThe spatial organization of deep moist convection is known to be an important determinant of the impacts of severe weather, while future changes to convective organization have been linked to various radiative feedbacks under climate warming. Yet there is no unanimously agreed upon definition of convective organization and so there is also no obvious way to objectively define it. In this work, we set out to define a metric for convective organization based on the size and proximity of convectively active regions. The metric is developed based upon tropical radar observations and takes two‐dimensional convective objects, which are predefined in a horizontal plane, as input. We call the metric Radar Organization Metric (ROME). In addition to the proximity of different convective objects, which is used in other organization metrics, ROME is also sensitive to object size. As a result, ROME is also defined for the case of only one convective object. Thus, ROME provides a smoothly evolving measure of the degree of convective organization, which compares well to a visual assessment of the convective objects. ROME is found to be sensitive to different regimes of the North Australian monsoon, and its average diurnal cycle is coherent with the daily evolution of tropical rainfall. Through its dependence on area, ROME adds new capabilities that other metrics lack in measuring the degree of convective organization. In particular, ROME permits quantification of the individual contributions of the object size distribution and the spatial clustering of objects to the overall degree of convective organization.
Position‐Based Wireless Channel Characterization for the High‐Speed Vactrains in Vacuum Tube Scenarios Using Propagation Graph Modeling Theory
Authors: Han Botao , Zhang Jiachi , Liu Liu , Tao Cheng 
Published: March 2020

AbstractWireless channel modeling is regarded as a pivotal research topic, since the analysis and evaluation of the wireless communication system requires a reliable model of the channel impulse response (CIR). This paper presents a novel and practical study on the position‐based radio propagation channel for high‐speed vactrains in the vacuum tube scenarios using the propagation graph channel modeling theory. Based on the Lambertian scattering pattern, the propagation graph channel modeling method considers the diffusion effect of radio waves. A multiple‐input multiple‐output (MIMO) wideband system channel is emulated for obtaining the virtual channel data. During the emulation process, the line‐of‐sight (LoS), single‐bounced and double‐bounced components are considered to yield the virtual CIR. Then, small‐scale fading properties such as K factor, time delay spread (DS), and Doppler frequency feature are parameterized particularly, which presents dynamic variances at different train locations. Moreover, the simulation performance analysis of the MIMO system focuses on the ergodic capacity and the singular value spread (SVS). The corresponding results indicate a MIMO capacity performance degradation in this scenario. The proposed model can facilitate the reliable simulation and evaluation of MIMO systems for the high‐speed vactrains in the vacuum tube scenarios.
Analysis and compensation of the rotor position offset error and time delay in field‐oriented‐controlled PMSM drives
Authors: Lian Chuanqiang , Xiao Fei , Liu Jilong , Gao Shan 
Published: March 2020

In high‐performance field‐oriented control of permanent magnet synchronous machines (PMSMs), an accurate rotor position is indispensable for the key roles in coordinate transformations. However, due to the rotor position offset error and the time delay in digital control systems, it is still challenging to obtain exact rotor position information. In this study, the influence of rotor position error on the control performance of a PMSM drive system is analysed first. Then, two novel compensation technologies, regulation and methods, are proposed to accurately compensate for the rotor position for both current and voltage coordinate transformations. The advantage of the proposed scheme is that even without any prior knowledge of the system delay, the rotor position offset and compensation time coefficients can also be precisely calculated. Parameter sensitivity analysis is carried out, and compensation criteria are also provided to improve the compensation accuracy. Experimental results on a 300 kW PMSM drive system demonstrate that compared to the results achieved with conventional methods, the compensation accuracies of the phase angles used for the current and voltage coordinate transformations are increased by and at 5000 r/min, respectively. Consequently, the control performance and stability margin of the system are efficiently improved.
Family of single‐phase isolated high‐frequency transformer integrated improved magnetically coupled Z‐source ac–ac converters
Authors: Ahmed Hafiz Furqan , El Moursi Mohamed Shawky , Irshad Tooba , El‐Saadany Ehab , Al Hosani Khalifa 
Published: March 2020

This study proposes single‐phase improved coupled‐inductor (CL) Z‐source (ZS) ac–ac converters with integrated high‐frequency transformer (HFT) isolation. They can provide wide range of buck–boost voltage with same/reversed phase angle, similar to the existing ZS ac–ac converters. Meanwhile, integrating a HFT with CL in proposed converters benefit in two‐fold: (i) the CL enhances the voltage gain, which in turn reduces the voltage stresses/ratings of active switches. Moreover, the turns ratio of CL add another degree of freedom to gain adjustment beside the duty ratio; (ii) the HFT (20 kHz) is integrated with CL by adding only one winding to the same magnetic core, which provides electrical isolation for applications such as dynamic voltage restore, saving extra bulky line frequency (60 Hz) transformer. In addition, the proposed converters provide both continuous input/output currents. The commutation strategy is also implemented to eliminate the switch voltage spikes. A proposed HFT isolated improved three‐winding Δ‐CL ZS (Δ‐ZS) ac–ac converter is introduced at first, and its operation, circuit analysis and component design/selection are discussed in detail along with comparisons with counterpart converters. Various different CL structures based proposed HFT isolated ZS ac–ac converters are presented afterwards. Experimental results on 200 W prototype converter are provided finally to verify their merits.
Detection of cimetidine in human plasma by surface‐enhanced Raman scattering
Authors: Zang Yingchao , Zhang Zhimin , Lu Hongmei 
Published: March 2020

This study describes a sensitive and rapid method for the quantification of Cimetidine (Cim) based on surface‐enhanced Raman scattering (SERS), using silver nanoparticles as an SERS substrate. Ag nanoparticle was fabricated by hydrothermal method. The experiment includes the selection of solvent types and optimisation of volume radio. Results suggested that the intensity and logarithmic Cim concentration in the range from 1.0 × 10−8 to 1.0 × 10−4 M has a linear relationship with the coefficient of determination (R 2) of 0.989, the limit of detection (LOD) of 2.9 × 10−9 M, by targeting the characteristic peak at 2150 cm−1. The LOD of Cim in plasma using this method was as low as 1 ng/ml. This indicates that the method has a potential for detection of Cim in biological samples.
Normalized angular momentum deficit: a tool for comparing the violence of the dynamical histories of planetary systems
Authors: Turrini D. , Zinzi A. , Belinchon J. A. 
Published: March 2020

Context. Population studies of the orbital characteristics of exoplanets in multi-planet systems have highlighted the existence of an anticorrelation between the average orbital eccentricity of planets and the number of planets of their host system, that is, its multiplicity. This effect was proposed to reflect the varying levels of violence in the dynamical evolution of planetary systems.
Aims. Previous work suggested that the relative violence of the dynamical evolution of planetary systems with similar orbital architectures can be compared through the computation of their angular momentum deficit (AMD). We investigated the possibility of using a more general metric to perform analogous comparisons between planetary systems with different orbital architectures.
Methods. We considered a modified version of the AMD, the normalized angular momentum deficit (NAMD), and used it to study a sample of 99 multi-planet systems containing both the currently best-characterized extrasolar systems and the solar system, that is, planetary systems with both compact and wide orbital architectures.
Results. We verified that the NAMD allows us to compare the violence of the dynamical histories of multi-planet systems with different orbital architectures. We identified an anticorrelation between the NAMD and the multiplicity of the planetary systems, of which the previously observed eccentricity–multiplicity anticorrelation is a reflection.
Conclusions. Our results seem to indicate that phases of dynamical instabilities and chaotic evolution are not uncommon among planetary systems. They also suggest that the efficiency of the planetary formation process in producing high-multiplicity systems is likely to be higher than that suggested by their currently known population.
Molecule formation in dust-poor irradiated jets
Authors: Tabone B. , Godard B. , Pineau des Forêts G. , Cabrit S. , van Dishoeck E. F. 
Published: March 2020

Context. Recent ALMA observations suggest that the highest velocity part of molecular protostellar jets (≳80 km s−1) are launched from the dust-sublimation regions of the accretion disks (≲0.3 au). However, the formation and survival of molecules in inner protostellar disk winds, in the presence of a harsh far-ultraviolet radiation field and the absence of dust, remains unexplored.
Aims. We aim to determine if simple molecules, such as H2, CO, SiO, and H2O, can be synthesized and spared in fast and collimated dust-free disk winds or if a fraction of dust is necessary to explain the observed molecular abundances.
Methods. This work is based on a recent version of the Paris-Durham shock code designed to model irradiated environments. Fundamental properties of the dust-free chemistry are investigated from single point models. A laminar 1D disk wind model was then built using a parametric flow geometry. This model includes time-dependent chemistry and the attenuation of the radiation field by gas-phase photoprocesses. The influence of the mass-loss rate of the wind and of the fraction of dust on the synthesis of the molecules and on the attenuation of the radiation field is studied in detail.
Results. We show that a small fraction of H2 (≤10−2), which primarily formed through the H− route, can efficiently initiate molecule synthesis, such as CO and SiO above TK ~ 800 K. We also propose new gas-phase formation routes of H2 that can operate in strong visible radiation fields, involving CH+ for instance. The attenuation of the radiation field by atomic species (e.g., C, Si, and S) proceeds through continuum self-shielding. This process ensures the efficient formation of CO, OH, SiO, and H2O through neutral–neutral reactions and the survival of these molecules. Class 0 dust-free winds with high mass-loss rates (Ṁw ≥ 2 × 10−6 M⊙ yr−1) are predicted to be rich in molecules if warm (TK ≥ 800 K). Interestingly, we also predict a steep decrease in the SiO-to-CO abundance ratio with the decline of mass-loss rate, from Class 0 to Class I protostars. The molecular content of disk winds is very sensitive to the presence of dust, and a mass-fraction of surviving dust as small as 10−5 significantly increases the H2O and SiO abundances.
Conclusions. Chemistry of high velocity jets is a powerful tool to probe their content in dust and uncover their launching point. Models of internal shocks are required to fully exploit the current (sub)millimeter observations and prepare future JWST observations.
High-Frequency Transient Elastography Prototype to Assess Skin (Dermis) Fibrosis: A Diagnostic Study in Patients with Venous Insufficiency and Controls
Authors: Mofid Yassine , Faleweei Geoffroy , Chartier Caroline , Machet Laurent , Vierron Emilie , Gissot Valerie , Tauveront Valerie , Georgescou Gabriela , Dujardin Paul-Armand , Machet Marie-Christine , Kervarrec Thibault , Patat Frédéric , Ossant Frederic , Maruani Annabel 
Published: March 2020

Abstract
Purpose High-frequency transient elastography (HF-TE) is a noninvasive technique for assessing shear-wave speed and finally elasticity in thin tissue such as the skin. It has never been validated for monitoring fibrotic skin diseases. The purpose was to evaluate the potential of HF-TE to assess skin fibrosis in patients with chronic venous disorders (CVD).
Materials and Methods This clinical study enrolled 48 patients at various stages of CVD and 48 paired healthy volunteers. Subjects underwent a clinical examination with an evaluation of Rodnan’s fibrosis skin score. We studied the dermis thickness measured using ultrasound (US) and elasticity measurements using cutometer and HF-TE studied according to 3 cutaneous zones positioned on the leg. The area under the receiver operating characteristic curve (AUC) was calculated to evaluate the diagnosis performance for a combined parameter (PRL) based on a logistic regression model using both elasticity and dermal thickness.
Results Patients with CVD had significantly higher values of skin elasticity than healthy subjects, 134.5 kPa and 132.1 kPa vs. 91.3 kPa, respectively. The dermis thickness also increased with escalation in CVD stage for all studied zones. The PRL parameter had an AUC value of 0.79 for all zones and stages of CVD clustered. The discriminating power of PRL increased with escalation of the CVD stage; with an AUC value of up to 0.89 for evolved stages, and a sensitivity and specificity of 0.79 and 0.89, respectively.
Conclusion HF-TE, coupled with a US measurement of dermis thickness, made it possible to propose a new biomarker, which proved to be a good diagnostic tool for skin fibrosis.
Erfolgreiche intraduktale Radiofrequenzablation residuellen Adenomgewebes nach endoskopischer Papillektomie
Authors: Gereitzig Nadine , Ziegan Ralf-Alexander , Tischendorf Jens J.W. 
Published: March 2020

ZusammenfassungDie Behandlung von Adenomen der Papilla duodeni major stellt für den Endoskopiker oft eine Herausforderung dar. Wir berichten über zwei Patienten mit Papillenadenomen, die nach endoskopischer Papillektomie jeweils zentral im Bereich der Mündung des Ductus hepatocholedochus ein Restadenom aufwiesen. Bei fehlender Möglichkeit einer weiteren endoskopischen Resektion erfolgte eine intraduktale Radiofrequenzablation anstelle einer chirurgischen Sanierung. Im Rahmen der Nachsorge ergaben sich weder makroskopisch noch histologisch Rezidive, sodass die intraduktale Radiofrequenzablation als Therapiealternative zur chirurgischen Versorgung zur Diskussion gestellt wird.