bluuebunny/crossref_metadata_2025 huggingface dataset:
Nuclear Star Clusters in Coma confirmation of an unusually high nucleation fraction
Authors: Zanatta Emilio , Sanchez-Janssen Ruben , Chies-Santos Ana L.
Published: March 2021

Nuclear star clusters (NSCs) are stellar systems similar in size to globular clusters (GCs) but extremely dense, comparable only to some GCs and ultra-compact dwarfs. They are present in galaxies with a wide range of masses, morphologies and gas content. There are several formation scenarios proposed for the formation of such objects, such as the merger of GCs or extreme star formation caused by the inflow of gas. Recent studies show that the presence of an NSC is related to galaxy stellar mass. Moreover, it has been suggested that NSCs are more often found in high density environments. In our work, we use deep imaging of the core regions of the Coma cluster down to an absolute magnitude of –8.2 and found that in this environment the nucleation fraction is higher than in the Virgo and Fornax clusters. We find nucleated galaxies in Coma as faint as –11.2 mag.
Multiwavelength analysis of OH Megamaser galaxies: The case of IRAS11506-3851
Authors: Hekatelyne Carpes P. , Storchi-Bergmann Thaisa
Published: March 2021

We present Multi-Object Spectrograph (GMOS) Integral Field Unit (IFU), Hubble Space Telescope (HST) and Very Large Array (VLA) observations of the inner kpc of the OH Megamaser galaxy IRAS 11506-3851. In this work we discuss the kinematics and excitation of the gas as well as its radio emission. The HST images reveal an isolated spiral galaxy and the combination with the GMOS-IFU flux distributions allowed us to identify a partial ring of star-forming regions surrounding the nucleus with a radius of ≍500 pc. The emission-line ratios and excitation map reveal that the region inside the ring present mixed/transition excitation between those of Starbursts and Active Galactic Nuclei (AGN), while regions along the ring are excited by Starbursts. We suggest that we are probing a buried or fading AGN that could be both exciting the gas and originating an outflow.
Spreading and Vertical Structure of the Persian Gulf and Red Sea Outflows in the Northwestern Indian Ocean
Authors: L'Hégaret Pierre , Marez Charly de , Morvan Mathieu , Meunier Thomas , Carton Xavier
Published: March 2021

In the Indian Ocean, salty water masses from the Persian Gulf and Red Sea are important sources of salt, heat, and nutrients. Across the Arabian Sea, these outflows impact human and biological activities, their thermohaline characteristics and shapes exhibiting important spatial and seasonal variability. The knowledge of the water masses properties is important to validate realistic simulations of the Indian Ocean. A classical approach to study these water masses is to track them on specific isopycnal levels. Nevertheless, their peaking thermohaline characteristics are not always found at a specific density but rather spread over a range. Here, we develop a detection algorithm able to capture the full vertical structure of the outflows, that we applied to a data set of about 126,000 vertical profiles. We are thus able to quantify the changes in their thermohaline signatures and in their vertical structures, characterized here by the intensity of the salinity peaks of the water masses and lateral injection of fresh and salty waters, and describe their spatial variability. Across the northwestern Indian Ocean, the salty outflows undergo several changes, diminishing their thermohaline signatures and peaks and layering. In their early stages in the narrow Gulf of Oman and Aden, the outflows present configurations indicative of diapycnal mixing. In the same regions and along the western edge of the Arabian Sea, these water masses are subject to lateral mixing. All over the Arabian Sea, salt fingering conditions are met for lower layers of the outflows.
Timescales of Partial Melting and Melt Crystallization in the Eastern Himalayan Orogen: Insights From Zircon Petrochronology
Authors: Ding Huixia , Zhang Zeming , Kohn Matthew J. , Gou Zhengbin
Published: March 2021

Revealing the timescales of metamorphic and anatectic processes is central to our understanding of tectonic evolution of collisional orogens. High‐temperature migmatites and leucogranites are well exposed in the Himalayan orogenic core, making it an ideal region to study the timing and duration of partial melting and melt crystallization of the orogen. Here, we report an integrated and comprehensive data set of petrography, U‐Pb age, and trace element data for zircon from a pelitic granulite and associated leucosomes of the Greater Himalayan Sequence (GHS) in the Yadong area, eastern Himalaya. Zircon grains with complex internal structure retain variable ages ranging from 32 Ma to 13 Ma that correlate systematically with changes in the concentrations of Y, Th, U, Hf, Nb, Ta, and HREE, and ratios of Th/U, Eu/Eu*, and Nb/Ta. Combined with petrologic analysis, we conclude that the granulite witnessed high‐temperature metamorphism, melting, and melt crystallization over ∼20 Myr. Prograde, simultaneous increases in pressure and temperature and associated dehydration melting began at least by ∼32 Ma and lasted until ∼24 Ma. Subsequent quasi‐isothermal decompression‐melting occurred between ∼22 and 19 Ma, and late melt crystallization spanned ∼19 to 13 Ma. Large volumes of melt generated during prograde metamorphism could have triggered exhumation of GHS rocks, increasing melt fraction through a positive feedback between exhumation and melting. More comprehensive analysis of different rock types led to more complete and different interpretations for the timing of exhumation and melt crystallization in the Yadong‐Sikkim region and might enable alternate interpretations elsewhere in the Himalayas.
SeismoGen: Seismic Waveform Synthesis Using GAN With Application to Seismic Data Augmentation
Authors: Wang Tiantong , Trugman Daniel , Lin Youzuo
Published: March 2021

Detecting earthquake arrivals within seismic time series can be a challenging task. Visual, human detection has long been considered the gold standard but requires intensive manual labor that scales poorly to large data sets. In recent years, automatic detection methods based on machine learning have been developed to improve the accuracy and efficiency. However, the accuracy of those methods relies on access to a sufficient amount of high‐quality labeled training data, often tens of thousands of records or more. We aim to resolve this dilemma by answering two questions: (1) provided with a limited amount of reliable labeled data, can we use them to generate additional, realistic synthetic waveform data? and (2) can we use those synthetic data to further enrich the training set through data augmentation, thereby enhancing detection algorithms? To address these questions, we use a generative adversarial network (GAN), a type of machine learning model which has shown supreme capability in generating high‐quality synthetic samples in multiple domains. Once trained, our GAN model is capable of producing realistic seismic waveforms of multiple labels (noise and event classes). Applied to real Earth seismic data sets in Oklahoma, we show that data augmentation from our GAN‐generated synthetic waveforms can be used to improve earthquake detection algorithms in instances when only small amounts of labeled training data are available.
On the Effect of Grain Fragmentation on Frictional Instabilities in Faults With Granular Gouge
Authors: Wang Di , Carmeliet Jan , Zhou Wei , Dorostkar Omid
Published: March 2021

The evolution of frictional strength during stick‐slip dynamics of a fault system is key to understanding earthquake nucleation and rupture patterns. In mature faults, granular gouge is produced by wear, comminution or fragmentation during tectonic movements. In this work, we introduce a fragmentation model in the simulation of a sheared granular fault to explore the influence of grain breakage on the stick‐slip dynamics. With fragmentation of highly stressed particles, the fault frictional strength increases accompanied by many small slip events triggered by particle breakage. The small fragments produced by particle breakage are not only stronger and more difficult to break, but they also change the distribution of contact forces, leading to the strengthening of the fault system. Based on statistical analyses on the size distribution of slip events with different particle strengths, we find that with lower particle strength, slip events become more correlated with particle fragmentation events and that the number of large slip events decreases. In addition, our analyses on the relationship between slip and particle fragmentation events reveal three types of correlations: In the first and second types, particle fragmentation events trigger micro or major slips, respectively. In the third category, large‐scale particle fragmentations take place at the end of large slip events owing to stress localization during post‐slip particle rearrangements. Our results in this work highlight the role of micromechanics of particle fragmentation in the failure of fault damage zones and help in understanding the relation between particle breakage and frictional failures.
Changes in Below‐Cloud Evaporation Affect Precipitation Isotopes During Five Decades of Warming Across China
Authors: Wang Shengjie , Jiao Rong , Zhang Mingjun , Crawford Jagoda , Hughes Catherine E. , Chen Fenli
Published: March 2021

Based on daily meteorological records for 651 sites across China during the period 1960–2018, we estimated the changes in isotopic variations in raindrops as they descend from cloud base to ground over past decades, and tested the sensitivity of isotopic variations to climate parameters like air temperature and relative humidity. Air temperature correlates positively and relative humidity correlates negatively with below‐cloud isotopic variation. Generally, the below‐cloud evaporation effect on precipitation isotopes in the arid and semi‐arid regions of China is much greater than that in the humid and semi‐humid regions, although the impact might be reduced under cold‐arid or hot‐humid conditions. With aridity increasing with distance from the coast, the continental effect of precipitation isotopes is modified due to the below‐cloud evaporation. The seasonal pattern of the measured isotopic composition in precipitation near the ground and estimated at cloud base, is still similar in most regions, although the seasonal range is higher at the ground. During the last five decades, the below‐cloud evaporation effect has enhanced for the cold and arid regions of China especially across Qinghai‐Tibet Plateau and Inner Mongolia, due to combined effects of increasing air temperature and decreasing relative humidity. Although the below‐cloud evaporation effect is not always the dominant factor influencing the variability of stable isotopes, it needs to be considered as one of the contributing factors. This enhanced effect may impact the interpretation of past climate based on stable water isotopes, particularly in paleoclimate studies using speleothems and tree rings.
A Lagrangian Stochastic Model of a Volcanic Eruption Column
Authors: Devenish B. J. , Cerminara M.
Published: March 2021

We present a Lagrangian stochastic model (LSM) of a volcanic plume in which the mean flow is provided by an integral plume model of the eruption column and fluctuations in the vertical velocity are modeled by a suitably constructed stochastic differential equation. This model is based on that of Bisignano and Devenish (2015,http://doi.org/10.1007/s10546-015-0055-3) with the mean flow provided by the integral plume model of Devenish (2013,http://doi.org/10.1016/j.jvolgeores.2013.02.015). The LSM is applied to the two eruptions considered by Costa et al. (2016,http://doi.org/10.1016/j.jvolgeores.2016.01.017) for the volcanic‐plume intercomparison study with no ambient wind and to the hypothetical cases with ambient wind considered by Aubry et al. (2019,http://doi.org/10.1029/2019GL083975). Vertical profiles of the mass concentration computed from the LSM are compared with equivalent results from large eddy simulations (LES). The LSM captures the order of magnitude of the LES mass concentrations and aspects of their profiles: for example, in contrast with a standard integral plume model, that is, without fluctuations, the mass concentration computed from the LSM decays (to zero) toward the top of the plume consistent with the LES plumes. In the lower part of the plume, we show that the presence of ash leads to a peak in the mass concentration at the level at which there is a transition from a negatively buoyant jet to a positively buoyant plume. A quantitative analysis of the cases with ambient wind shows generally good agreement between the LSM and the LES for a number of quantities including the maximum concentration, the level at which it occurs, the maximum rise height, and the total erupted mass.
Towards automatic freeform optics design: coarse and fine search of the three-mirror solution space
Authors: Zhang Benqi , Jin Guofan , Zhu Jun
Published: March 2021

Design of an optical system, whether classic or novel, in the past or the present, requires significant effort from the designer. In addition to design methods and theories, the designer’s skills and experience in optical system design are particularly important, which may require years of practice to learn. The diversity and variety of results are limited because of the difficulty, time, and labor costs required. In this article, we propose an automatic design method for freeform optics that can achieve a diverse range of three-mirror designs. The optical specifications and the design constraints are the only inputs required, and a variety of results can be obtained automatically. The output results have various structures and various optical power distributions with high imaging qualities. By implementing the design method, designers can not only realize an overview of the solution space of the three-mirror freeform system, but can also focus on specific designs.
Cancer-associated fibroblasts-mediated ATF4 expression promotes malignancy and gemcitabine resistance in pancreatic cancer via the TGF-β1/SMAD2/3 pathway and ABCC1 transactivation
Authors: Wei Lusheng , Lin Qing , Lu Yanan , Li Guolin , Huang Leyi , Fu Zhiqiang , Chen Rufu , Zhou Quanbo
Published: March 2021

Cancer-associated fibroblasts (CAFs) contribute to malignant progression and chemoresistance in pancreatic ductal adenocarcinoma (PDAC). However, little is known about the underlying mechanism. In this study, we investigated the potential role and mechanisms of activating transcription factor 4 (ATF4) in CAFs-induced malignancy and gemcitabine resistance. We demonstrated that ATF4 is overexpressed in PDAC and associated with a poor prognosis. Silencing ATF4 expression decreased proliferation, colony formation, migration, gemcitabine sensitivity, and sphere formation. Subsequently, we revealed that CAFs secrete TGF-β1 to upregulate the expression of ATF4 in PDAC cells via the SMAD2/3 pathway and induce cancer progression, cancer stemness, and gemcitabine resistance. Furthermore, we demonstrated that ATF4 directly binds to the ABCC1 promoter region to activate transcription. In summary, these data demonstrate that CAFs contribute to malignancy and gemcitabine resistance in PDAC by upregulating the expression of ATF4 via the TGF-β1/SMAD2/3 axis and highlight that ATF4 is an attractive therapeutic target for combating gemcitabine resistance in PDAC.
HOXBLINC long non-coding RNA activation promotes leukemogenesis in NPM1-mutant acute myeloid leukemia
Authors: Zhu Ganqian , Luo Huacheng , Feng Yang , Guryanova Olga A. , Xu Jianfeng , Chen Shi , Lai Qian , Sharma Arati , Xu Bing , Zhao Zhigang , Feng Ru , Ni Hongyu , Claxton David , Guo Ying , Mesa Ruben A. , Qiu Yi , Yang Feng-Chun , Li Wei , Nimer Stephen D. , Huang Suming , Xu Mingjiang
Published: March 2021

Nucleophosmin (NPM1) is the most commonly mutated gene in acute myeloid leukemia (AML) resulting in aberrant cytoplasmic translocation of the encoded nucleolar protein (NPM1c+). NPM1c+ maintains a unique leukemic gene expression program, characterized by activation of HOXA/B clusters and MEIS1 oncogene to facilitate leukemogenesis. However, the mechanisms by which NPM1c+ controls such gene expression patterns to promote leukemogenesis remain largely unknown. Here, we show that the activation of HOXBLINC, a HOXB locus-associated long non-coding RNA (lncRNA), is a critical downstream mediator of NPM1c+-associated leukemic transcription program and leukemogenesis. HOXBLINC loss attenuates NPM1c+-driven leukemogenesis by rectifying the signature of NPM1c+ leukemic transcription programs. Furthermore, overexpression of HoxBlinc (HoxBlincTg) in mice enhances HSC self-renewal and expands myelopoiesis, leading to the development of AML-like disease, reminiscent of the phenotypes seen in the Npm1 mutant knock-in (Npm1c/+) mice. HoxBlincTg and Npm1c/+ HSPCs share significantly overlapped transcriptome and chromatin structure. Mechanistically, HoxBlinc binds to the promoter regions of NPM1c+ signature genes to control their activation in HoxBlincTg HSPCs, via MLL1 recruitment and promoter H3K4me3 modification. Our study reveals that HOXBLINC lncRNA activation plays an essential oncogenic role in NPM1c+ leukemia. HOXBLINC and its partner MLL1 are potential therapeutic targets for NPM1c+ AML.
Development of highly efficient platinum catalysts for hydroalkoxylation and hydroamination of unactivated alkenes
Authors: Zhou Yali , Xu Xingjun , Sun Hongwei , Tao Guanyu , Chang Xiao-Yong , Xing Xiangyou , Chen Bo , Xu Chen
Published: March 2021

Hydrofunctionalization, the direct addition of an X–H (e.g., X=O, N) bond across an alkene, is a desirable strategy to make heterocycles that are important structural components of naturally occurring molecules. Described here is the design and discovery of “donor–acceptor”-type platinum catalysts that are highly effective in both hydroalkoxylation and hydroamination of unactivated alkenes over a broad range of substrates under mild conditions. A number of alkene substitution patterns are accommodated, including tri-substituted, 1,1-disubstituted, (E)-disubstituted, (Z)-disubstituted and even mono-substituted double bonds. Detailed mechanistic investigations suggest a plausible pathway that includes an unexpected dissociation/re-association of the electron-deficient ligand to form an alkene-bound “donor–acceptor”-type intermediate. These mechanistic studies help understand the origins of the high reactivity exhibited by the catalytic system, and provide a foundation for the rational design of chiral catalysts towards asymmetric hydrofunctionalization reactions.
Application of chemometrics for modeling and optimization of ultrasound-assisted dispersive liquid–liquid microextraction for the simultaneous determination of dyes
Authors: Shojaei Siroos , Shojaei Saeed , Nouri Arezoo , Baharinikoo Leila
Published: March 2021

As the world population continues to grow, so does the pollution of water resources. It is, therefore, important to identify ways of reducing pollution as part of our effort to significantly increase the supply of clean and safer water. In this study, the efficiency of ultrasound-assisted dispersive liquid–liquid microextraction (UA-DLLME) as a fast, economical, and simple method for extraction malachite green (MG) and rhodamine B (RB) dyes from water samples is investigated. In optimal conditions, the linear dynamic range (LDR) for RB and MG is 7.5–1500 ng mL−1 and 12–1000 ng mL−1, respectively. The limit of detection (LOD) is 1.45 ng mL−1 and 2.73 ng mL−1, and limit of quantification (LOQ) is 4.83 ng mL−1 and 9.10 ng mL−1 for RB and MG, respectively. Extraction efficiency is obtained in the range of 95.53–99.60%. The relative standard deviations (RSD) in real water and wastewater samples are less than 3.5. The developed method is used successfully in the determination of RB and MG dyes from water samples and there are satisfactory results.
Solid state phase transformation kinetics in Zr-base alloys
Authors: Massih A. R. , Jernkvist Lars O.
Published: March 2021

We present a kinetic model for solid state phase transformation ($$\alpha \rightleftharpoons \beta$$

α
⇌
β

) of common zirconium alloys used as fuel cladding material in light water reactors. The model computes the relative amounts of $$\beta$$
β
or $$\alpha$$
α
phase fraction as a function of time or temperature in the alloys. The model accounts for the influence of excess oxygen (due to oxidation) and hydrogen concentration (due to hydrogen pickup) on phase transformation kinetics. Two variants of the model denoted by A and B are presented. Model A is suitable for simulation of laboratory experiments in which the heating/cooling rate is constant and is prescribed. Model B is more generic. We compare the results of our model computations, for both A and B variants, with accessible experimental data reported in the literature covering heating/cooling rates of up to 100 K/s. The results of our comparison are satisfactory, especially for model A. Our model B is intended for implementation in fuel rod behavior computer programs, applicable to a reactor accident situation, in which the Zr-based fuel cladding may go through $$\alpha \rightleftharpoons \beta$$

α
⇌
β

phase transformation.
Human health impact assessment and temporal distribution of trace elements in Copșa Mică- Romania
Authors: Bodor Katalin , Bodor Zsolt , Szép Alexandru , Szép Róbert
Published: March 2021

The present study aims to analyze the temporal variations of PM10 and to assess the health risk indexes caused by trace elements from particulate matter (PM10) via inhalation, ingestion, and dermal absorption by adults and children in Copșa Mică (Romania) during 2009–2019. The results revealed a high multi-annual mean concentration of PM10 and trace elements. The analyzed air pollutants showed a decreasing trend during the studied years, therefore 44.11%, 43.48%, 36.07%, 16.02%, and 15.80% lower values were observed for As, Cd, Ni, PM10, and Pb, respectively, due to environmental regulations. The daily exceedance percentage of Pb and Cd was very high, representing 21.74% and 11.26%, followed by PM10 and As concentrations with 4.72% and 3.92%. The ratio between the trace element concentration measured in Copșa Mică and the country average was 2.46, 4.01, 2.44 and 10.52 times higher for As, Cd, Ni and Pb. The calculated Hazard Quotient values via inhalation were higher than the safe limit (1), which accounted 1.81, 3.89 and 4.52, for As, Cd and Ni, respectively, indicating that the trace elements might present a non-carcinogenic risk to both adults and children. Furthermore, the concentration of all studied trace elements in Copșa Mică showed cancer risk for adults via inhalation and dermal absorption as well.
Ordinal classification of the affectation level of 3D-images in Parkinson diseases
Authors: Durán-Rosal Antonio M. , Camacho-Cañamón Julio , Gutiérrez Pedro Antonio , Guiote Moreno Maria Victoria , Rodríguez-Cáceres Ester , Vallejo Casas Juan Antonio , Hervás-Martínez César
Published: March 2021

Parkinson’s disease is characterised by a decrease in the density of presynaptic dopamine transporters in the striatum. Frequently, the corresponding diagnosis is performed using a qualitative analysis of the 3D-images obtained after the administration of$$^{123}$$123I-ioflupane, considering a binary classification problem (absence or existence of Parkinson’s disease). In this work, we propose a new methodology for classifying this kind of images in three classes depending on the level of severity of the disease in the image. To tackle this problem, we use an ordinal classifier given the natural order of the class labels. A novel strategy to perform feature selection is developed because of the large number of voxels in the image, and a method for generating synthetic images is proposed to improve the quality of the classifier. The methodology is tested on 434 studies conducted between September 2015 and January 2019, divided into three groups: 271 without alteration of the presynaptic nigrostriatal pathway, 73 with a slight alteration and 90 with severe alteration. Results confirm that the methodology improves the state-of-the-art algorithms, and that it is able to find informative voxels outside the standard regions of interest used for this problem. The differences are assessed by statistical tests which show that the proposed image ordinal classification could be considered as a decision support system in medicine.
Use of propensity score matching to create counterfactual group to assess potential HIV prevention interventions
Authors: Abaasa Andrew , Mayanja Yunia , Asiki Gershim , Price Matt A. , Fast Patricia E. , Ruzagira Eugene , Kaleebu Pontiano , Todd Jim
Published: March 2021

The design of HIV prevention trials in the context of effective HIV preventive methods is a challenge. Alternate designs, including using non-randomised ‘observational control arms’ have been proposed. We used HIV simulated vaccine efficacy trials (SiVETs) to show pitfalls that may arise from using such observational controls and suggest how to conduct the analysis in the face of the pitfalls. Two SiVETs were nested within previously established observational cohorts of fisherfolk (FF) and female sex workers (FSW) in Uganda. SiVET participants received a licensed Hepatitis B vaccine in a schedule (0, 1 and 6 months) similar to that for a possible HIV vaccine efficacy trial. All participants received HIV counselling and testing every quarter for one year to assess HIV incidence rate ratio (IRR) between SiVET and non-SiVET (observational data). Propensity scores, conditional on baseline characteristics were calculated for SiVET participation and matched between SiVET and non-SiVET in the period before and during the SiVET study. We compared IRR before and after propensity score matching (PSM). In total, 3989 participants were enrolled into observational cohorts prior to SiVET, (1575 FF prior to Jul 2012 and 2414 FSW prior to Aug 2014). SiVET enrolled 572 participants (Jul 2012 to Apr 2014 in FF and Aug 2014 to Apr 2017 in FSW), with 953 non-SiVET participants observed in the SiVET concurrent period and 2928 from the pre-SiVET period (before Jul 2012 in FF or before Apr 2014 in FSW). Imbalances in baseline characteristics were observed between SiVET and non-SiVET participants in both periods before PSM. Similarly, HIV incidence was lower in SiVET than non-SiVET; SiVET-concurrent period, IRR = 0.59, 95% CI 0.31–0.68, p = 0.033 and pre-SiVET period, IRR = 0.77, 95% CI 0.43–1.29, p = 0.161. After PSM, participants baseline characteristics were comparable and there were minimal differences in HIV incidence between SiVET and non-SiVET participants. The process of screening for eligibility for efficacy trial selects participants with baseline characteristics different from the source population, confounding any observed differences in HIV incidence. Propensity score matching can be a useful tool to adjust the imbalance in the measured participants’ baseline characteristics creating a counterfactual group to estimate the effect of interventions on HIV incidence.
Detection of extended spectrum beta-lactamase genes in Pseudomonas aeruginosa isolated from patients in rural Eastern Cape Province, South Africa
Authors: Hosu Mojisola C. , Vasaikar Sandeep D. , Okuthe Grace E. , Apalata Teke
Published: March 2021

The proliferation of extended spectrum beta-lactamase (ESBL) producing Pseudomonas aeruginosa represent a major public health threat. In this study, we evaluated the antimicrobial resistance patterns of P. aeruginosa strains and characterized the ESBLs and Metallo- β-lactamases (MBL) produced. Strains of P. aeruginosa cultured from patients who attended Nelson Mandela Academic Hospital and other clinics in the four district municipalities of the Eastern Cape between August 2017 and May 2019 were identified; antimicrobial susceptibility testing was carried out against thirteen clinically relevant antibiotics using the BioMérieux VITEK 2 and confirmed by Beckman autoSCAN-4 System. Real-time PCR was done using Roche Light Cycler 2.0 to detect the presence of ESBLs; blaSHV, blaTEM and blaCTX-M genes; and MBLs; blaIMP, blaVIM. Strains of P. aeruginosa demonstrated resistance to wide-ranging clinically relevant antibiotics including piperacillin (64.2%), followed by aztreonam (57.8%), cefepime (51.5%), ceftazidime (51.0%), piperacillin/tazobactam (50.5%), and imipenem (46.6%). A total of 75 (36.8%) multidrug-resistant (MDR) strains were observed of the total pool of isolates. The blaTEM, blaSHV and blaCTX-M was detected in 79.3%, 69.5% and 31.7% isolates (n = 82), respectively. The blaIMP was detected in 1.25% while no blaVIM was detected in any of the strains tested. The study showed a high rate of MDR P. aeruginosa in our setting. The vast majority of these resistant strains carried blaTEM and blaSHV genes. Continuous monitoring of antimicrobial resistance and strict compliance towards infection prevention and control practices are the best defence against spread of MDR P. aeruginosa.
Anti-estrogenic and anti-aromatase activities of citrus peels major compounds in breast cancer
Authors: El-Kersh Dina M. , Ezzat Shahira M. , Salama Maha M. , Mahrous Engy A. , Attia Yasmeen M. , Ahmed Mahmoud Salama , Elmazar Mohey M.
Published: March 2021

Estrogen signaling is crucial for breast cancer initiation and progression. Endocrine-based therapies comprising estrogen receptor (ER) modulators and aromatase inhibitors remain the mainstay of treatment. This study aimed at investigating the antitumor potential of the most potent compounds in citrus peels on breast cancer by exploring their anti-estrogenic and anti-aromatase activities. The ethanolic extract of different varieties of citrus peels along with eight isolated flavonoids were screened against estrogen-dependent breast cancer cell lines besides normal cells for evaluating their safety profile. Naringenin, naringin and quercetin demonstrated the lowest IC50sand were therefore selected for further assays. In silico molecular modeling against ER and aromatase was performed for the three compounds. In vivo estrogenic and anti-estrogenic assays confirmed an anti-estrogenic activity for the isolates. Moreover, naringenin, naringin and quercetin demonstrated in vitro inhibitory potential against aromatase enzyme along with anticancer potential in vivo, as evidenced by decreased tumor volumes. Reduction in aromatase levels in solid tumors was also observed in treated groups. Overall, this study suggests an antitumor potential for naringenin, naringin and quercetin isolated from citrus peels in breast cancer via possible modulation of estrogen signaling and aromatase inhibition suggesting their use in pre- and post-menopausal breast cancer patients, respectively.
Applying a hierarchical clustering on principal components approach to identify different patterns of the SARS-CoV-2 epidemic across Italian regions
Authors: Maugeri Andrea , Barchitta Martina , Basile Guido , Agodi Antonella
Published: March 2021

Italy has experienced the epidemic of Severe Acute Respiratory Syndrome Coronavirus 2, which spread at different times and with different intensities throughout its territory. We aimed to identify clusters with similar epidemic patterns across Italian regions. To do that, we defined a set of regional indicators reflecting different domains and employed a hierarchical clustering on principal component approach to obtain an optimal cluster solution. As of 24 April 2020, Lombardy was the worst hit Italian region and entirely separated from all the others. Sensitivity analysis—by excluding data from Lombardy—partitioned the remaining regions into four clusters. Although cluster 1 (i.e. Veneto) and 2 (i.e. Piedmont and Emilia-Romagna) included the most hit regions beyond Lombardy, this partition reflected differences in the efficacy of restrictions and testing strategies. Cluster 3 was heterogeneous and comprised regions where the epidemic started later and/or where it spread with the lowest intensity. Regions within cluster 4 were those where the epidemic started slightly after Veneto, Emilia-Romagna and Piedmont, favoring timely adoption of control measures. Our findings provide policymakers with a snapshot of the epidemic in Italy, which might help guiding the adoption of countermeasures in accordance with the situation at regional level.
Federated deep learning for detecting COVID-19 lung abnormalities in CT: a privacy-preserving multinational validation study
Authors: Dou Qi , So Tiffany Y. , Jiang Meirui , Liu Quande , Vardhanabhuti Varut , Kaissis Georgios , Li Zeju , Si Weixin , Lee Heather H. C. , Yu Kevin , Feng Zuxin , Dong Li , Burian Egon , Jungmann Friederike , Braren Rickmer , Makowski Marcus , Kainz Bernhard , Rueckert Daniel , Glocker Ben , Yu Simon C. H. , Heng Pheng Ann
Published: March 2021

Data privacy mechanisms are essential for rapidly scaling medical training databases to capture the heterogeneity of patient data distributions toward robust and generalizable machine learning systems. In the current COVID-19 pandemic, a major focus of artificial intelligence (AI) is interpreting chest CT, which can be readily used in the assessment and management of the disease. This paper demonstrates the feasibility of a federated learning method for detecting COVID-19 related CT abnormalities with external validation on patients from a multinational study. We recruited 132 patients from seven multinational different centers, with three internal hospitals from Hong Kong for training and testing, and four external, independent datasets from Mainland China and Germany, for validating model generalizability. We also conducted case studies on longitudinal scans for automated estimation of lesion burden for hospitalized COVID-19 patients. We explore the federated learning algorithms to develop a privacy-preserving AI model for COVID-19 medical image diagnosis with good generalization capability on unseen multinational datasets. Federated learning could provide an effective mechanism during pandemics to rapidly develop clinically useful AI across institutions and countries overcoming the burden of central aggregation of large amounts of sensitive data.
Diapause vs. reproductive programs: transcriptional phenotypes in a keystone copepod
Authors: Lenz Petra H. , Roncalli Vittoria , Cieslak Matthew C. , Tarrant Ann M. , Castelfranco Ann M. , Hartline Daniel K.
Published: March 2021

Many arthropods undergo a seasonal dormancy termed “diapause” to optimize timing of reproduction in highly seasonal environments. In the North Atlantic, the copepodCalanus finmarchicuscompletes one to three generations annually with some individuals maturing into adults, while others interrupt their development to enter diapause. It is unknown which, why and when individuals enter the diapause program. Transcriptomic data from copepods on known programs were analyzed using dimensionality reduction of gene expression and functional analyses to identify program-specific genes and biological processes. These analyses elucidated physiological differences and established protocols that distinguish between programs. Differences in gene expression were associated with maturation of individuals on the reproductive program, while those on the diapause program showed little change over time. Only two of six filters effectively separated copepods by developmental program. The first one included all genes annotated to RNA metabolism and this was confirmed using differential gene expression analysis. The second filter identified 54 differentially expressed genes that were consistently up-regulated in individuals on the diapause program in comparison with those on the reproductive program. Annotated to oogenesis, RNA metabolism and fatty acid biosynthesis, these genes are both indicators for diapause preparation and good candidates for functional studies.
Atomic layer deposition of LiF using LiN(SiMe3)2 and SF6 plasma
Authors: Hornsveld N. , Kessels W. M. M. , Synowicki R. A. , Creatore M.
Published: March 2021

Lithium fluoride films were prepared by atomic layer deposition (ALD) using a new route in which LiN(SiMe3)2 is used as a precursor and SF6 plasma as a coreactant. It was demonstrated that SF6 plasma is a promising coreactant for ALD of high purity lithium fluoride films.
Synergizing the potential of bacterial genomics and metabolomics to find novel antibiotics
Authors: Panter Fabian , Bader Chantal D. , Müller Rolf
Published: March 2021

Antimicrobial resistance is a major public concern and novel antibiotics are largely based on natural products. We summarize recent analytical and genome based technological developments that gain increasing importance in the natural products field.
Cellulose acetate containing CaO coated on polypropylene for enhanced thermal stability of separator
Authors: Lee Hye Ji , Kang Sang Wook
Published: March 2021

Incorporation of calcium oxide to cellulose acetate the formation of network structure by interactions of particle with polymer chains the pore–connection through cellulose acetate and polypropylene for enhanced stability.
N-Hydroxyphthalimidyl diazoacetate (NHPI-DA): a modular methylene linchpin for the C–H alkylation of indoles
Authors: Chowdhury Rajdip , Mendoza Abraham
Published: March 2021

The insertion of conventional diazocompounds into indoles are still limited by the custom carbene precursors, catalysts and manipulation of the products required. Herein, we address these shortcomings with a redox-active carbene precursor (NHPI-DA).
Tuneable structures and magnetic properties of pseudohalo-bridged dinuclear Ni(ii) complexes derived from {N4} and {N3O} donor ligands
Authors: Adak Sarmistha , Sun Yu-Chen , Jana Narayan Ch. , Brandão Paula , Wang Xin-Yi , Panja Anangamohan
Published: March 2021

Six new dinickel(ii) complexes with different bridges and bridging motifs showing overall diverse magnetic interactions (AF to F interactions) have been discussed and rationalized.
Effects of growth substrate on the nucleation of monolayer MoTe2
Authors: Hynek David J. , Singhania Raivat M. , Hart James L. , Davis Benjamin , Wang Mengjing , Strandwitz Nicholas C. , Cha Judy J.
Published: March 2021

Choice of growth substrate is shown to have a significant effect on the conversion of ALD grown molybdenum oxide to monolayer 2H molybdenum ditelluride.
Electron-induced fragmentation mechanisms in organic monomers and their implications for photoresist optimization for EUV lithography
Authors: Rathore Ashish , Cipriani Maicol , Huang Ching-Chung , Amiaud Lionel , Dablemont Céline , Lafosse Anne , Ingólfsson Oddur , De Simone Danilo , De Gendt Stefan
Published: March 2021

The electron-induced fragmentation mechanisms of two important EUV-photoresist monomers methyl isobutyrate and methacrylic acid are investigated in the film and gas-phases.
Temperature dependencies of the degradation of NO, NO2 and HONO on a photocatalytic dispersion paint
Authors: Pill Daniela , Wiesen Peter , Kleffmann Jörg
Published: March 2021

Decoupling of the complex humidity and temperature dependencies of the NO, NO2 and HONO uptake on a photocatalytic paint.
Mechanical properties of aerospace epoxy composites reinforced with 2D nano-fillers: current status and road to industrialization
Authors: Wazalwar Radhika , Sahu Megha , Raichur Ashok M.
Published: March 2021

This review offers a comprehensive literature survey and a perspective into the possible ways of bridging the gaps between the laboratory research and industrialization of 2D nanosheet-filled epoxy composites.
A novel column modification approach for capillary gas chromatography: combination with a triptycene-based stationary phase achieves high separation performance and inertness
Authors: He Yongrui , Qi Meiling
Published: March 2021

Integration of the novel column modification approach with a triptycene-based stationary phase achieves high-resolution performance and inertness towards acids/bases and isomers for capillary GC analysis.
Rapid and simultaneous detection of heart-type fatty acid binding protein and cardiac troponin using a lateral flow assay based on metal organic framework@CdTe nanoparticles
Authors: Zou Jian , Liu Xin , Ren Xiangling , Tan Longfei , Fu Changhui , Wu Qiong , Huang Zhongbing , Meng Xianwei
Published: March 2021

Multicolor ZrMOF@CdTe NPs for simultaneous detection of h-FABP and cTnT.
Discovery of a highly efficient nitroaryl group for detection of nitroreductase and imaging of hypoxic tumor cells
Authors: Wang Shushu , Wu Xiaojun , Zhang Yuqing , Zhang Dong , Xie Boyu , Pan Zhixiang , Ouyang Kunfu , Peng Tao
Published: March 2021

Comparison of different nitroaryl groups revealed 2-nitro-N-methyl-imidazolyl as the optimal nitroaryl substrate for developing highly efficient nitroreductase fluorescent probes.
NIS-promoted three-component reaction of 3-oxo-3-arylpropanenitriles with arylsulfonyl hydrazides
Authors: Wei Yueting , Liu Ping , Liu Yali , He Jing , Li Xuezhen , Li Shiwu , Zhao Jixing
Published: March 2021

An expanded inventory of 3-aryl-4-(arylthio)-1H-pyrazol-5-amines were synthesized by a new three-component reaction of 3-oxo-3-arylpropanenitriles with arylsulfonyl hydrazides under the action of NIS.
Sky-blue thermally activated delayed fluorescence polymers by using a conjugation-confined poly(aryl ether) main chain
Authors: Chen Tianheng , Chen Zhanxiang , Ni Fan , Xie Guohua , Yang Chuluo
Published: March 2021

A series of sky-blue TADF polymers were developed by applying a bipolar poly(aryl ether) main chain, and solution-processed OLEDs with these polymers doped into the host DMAC-DP-CZ showed high external quantum efficiencies of up to 14.5%.
A multi-responsive self-healing hydrogel for controlled release of curcumin
Authors: Pan Ruihao , Liu Guoqiang , Zeng Yuan , He Xianzhe , Ma Zeyu , Wei Yen , Chen Shengli , Yang Lei , Tao Lei
Published: March 2021

A multi-responsive self-healing hydrogel for the controlled release of curcumin has been developed using dynamic boronic acid ester linkages.
A defective MoS2 monolayer as an efficient electrocatalyst for the nitrogen reduction reaction: a combined theoretical and experimental study
Authors: Ma Chaoqun , Yan Xu , He Hui , Liu Bingping , Yan Shihai
Published: March 2021

The enzymatic mechanism dominates the NRR on S vacancy defective MoS2 (VS-MoS2). Experimentally, VS-MoS2 exhibits higher yield (29.55 μg h−1 mgcat.−1) and faradaic efficiency (4.58%) than other defective MoS2 catalysts.
Deaminated purine bypass by DNA polymerase η
Authors: Andreeva Antonina
Published: March 2021

A recent work by Jung and colleagues (Biochem J.477, 4797–4810) provides an explanation of how DNA polymerase η replicates through deaminated purine bases such as xanthine and hypoxanthine. This commentary discusses the crystal structures of the polymerase η complexes that implicate the role of tautomerism in the bypass of these DNA lesions.
Elongation factor eEF2 kinase and autophagy jointly promote survival of cancer cells
Authors: Lenchine Roman V. , Rao Sushma R. , Wang Xuemin , Fang Danielle Meiwen , Proud Christopher G.
Published: March 2021

Cells within solid tumours can become deprived of nutrients; in order to survive, they need to invoke mechanisms to conserve these resources. Using cancer cells in culture in the absence of key nutrients, we have explored the roles of two potential survival mechanisms, autophagy and elongation factor 2 kinase (eEF2K), which, when activated, inhibits the resource-intensive elongation stage of protein synthesis. Both processes are regulated through the nutrient-sensitive AMP-activated protein kinase and mechanistic target of rapamycin complex 1 signalling pathways. We find that disabling both autophagy and eEF2K strongly compromises the survival of nutrient-deprived lung and breast cancer cells, whereas, for example, knocking out eEF2K alone has little effect. Contrary to some earlier reports, we find no evidence that eEF2K regulates autophagy. Unexpectedly, eEF2K does not facilitate survival of prostate cancer PC3 cells. Thus, eEF2K and autophagy enable survival of certain cell-types in a mutually complementary manner. To explore this further, we generated, by selection, cells which were able to survive nutrient starvation even when autophagy and eEF2K were disabled. Proteome profiling using mass spectrometry revealed that these ‘resistant’ cells showed lower levels of diverse proteins which are required for energy-consuming processes such as protein and fatty acid synthesis, although different clones of ‘resistant cells’ appear to adapt in dissimilar ways. Our data provide further information of the ways that human cells cope with nutrient limitation and to understanding of the utility of eEF2K as a potential target in oncology.
Is the classical oral antidiabetic metformin the novel miracle drug to combat aging?
Authors: Glossmann Hartmut H. , Lutz Oliver M. D.
Published: March 2021

Metformin is first or second choice for oral treatment of type 2 diabetes and is licensed for its prevention. Numerous articles propagate metformin as a drug that combats diseases and lowers the risks that are associated with advanced chronological age, such as cancer, diabetes, frailty, coronary heart disease and, most recently, even COVID-19. However, no clinical studies yet exist which prove that metformin delays the onset of such age-related diseases in elderly healthy individuals. Metformin – contrary to expectations – interferes with the beneficial effects of endurance or resistance training, is suspected to rapidly lead to mild anaemia and proven to cause vitamin B12 deficiency.
Coordinated collision avoidance for multi‐vehicle systems based on collision time
Authors: Yu Hongjun , Wang Ying , Liang Lihua , Shi Peng
Published: March 2021

Vehicles have irregular shapes and inter‐vehicle coordination is not a trivial task. Based on the distributed‐system framework, this paper studies multi‐vehicle control and coordinated obstacle avoidance for multiple autonomous vehicles with irregular shapes. The goal is to reach target points without collisions. The proposed approaches are based on collision time, which is calculated using vehicles' irregular shapes. The approaches have two parts. The first part enables a number of vehicles to reach the target points. The second part enables collision avoidance, which includes inter‐vehicle collisions and vehicle‐to‐obstacle collisions. Speed regulation approach is proposed to change the speeds, and frequency‐modulation approach is proposed to update control commands at varying steps, and a combined approach is also proposed. Simulation examples are set to verify the effectiveness of the proposed approaches.
Sensing accuracy enhancement of long‐range distributed fibre‐optic temperature sensor using hybrid algorithm
Authors: Pradhan Himansu Shekhar
Published: March 2021

This paper presents a long‐range distributed fibre‐optic temperature sensor with high sensing accuracy to monitor temperature using Brillouin scattering mechanism. Fourier deconvolution, Fourier wavelet regularised deconvolution, dichotomised singular value decomposition and hybrid algorithms were employed to measure the temperature of proposed sensor. Optical time domain reflectometry technique is used to extract the temperature profile for 70, 60 and 50 km sensing ranges. The improvement of temperature accuracy using hybrid algorithm is achieved for 70 km sensing distance. In order to extract temperature information, the numerical simulation process has been incorporated in the proposed long‐range sensing system. Moreover, the temperature accuracy of the proposed system is obtained using Fourier deconvolution, Fourier wavelet regularised deconvolution, dichotomised singular value decomposition and hybrid algorithms for 70, 60 and 50 km sensing ranges. The simulation results show that the temperature accuracy is observed as 4.8°K using hybrid algorithm compared to Fourier deconvolution algorithm that shows temperature accuracy as 14°K at 70 km. In the proposed sensor, a spatial resolution of 20 m is observed for a sensing range of 70 km using hybrid algorithm. In addition, the denoising competence of the proposed hybrid algorithm is validated using 50 km optical time domain reflectometry backscattered trace observed experimentally. Further, a peak dynamic range improvement of optical time domain reflectometry backscattered trace as 3.91 dB is observed using hybrid algorithm.