bluuebunny/crossref_metadata_2025 huggingface dataset:
The morphological and chemical properties of fine roots respond to nitrogen addition in a temperate Schrenk’s spruce (Picea schrenkiana) forest
Authors: Zhu Haiqiang , Zhao Jingjing , Gong Lu
Published: February 2021

Fine roots (< 2 mm in diameter) play an important role in belowground ecosystem processes, and their physiological ecology is easily altered by nitrogen deposition. To better understand the response of physiological and ecological processes of fine roots to nitrogen deposition, a manipulation experiment was conducted to investigate the effects of exogenous nitrogen addition (control (0 kg ha−1 a−1), low (5 kg ha−1 a−1), moderate (10 kg ha−1 a−1), and high nitrogen (20 kg ha−1 a−1)) on the biomass, morphological characteristics, chemical elements and nonstructural carbohydrates of fine roots in a Picea schrenkiana forest. We found that most fine roots were located in the 0–20 cm of soil layer across all nitrogen treatment groups (42.81–52.09% of the total biomass). Compared with the control, the biomass, specific root length and specific root area of the fine roots increased in the medium nitrogen treatment, whereas the fine roots biomass was lower in the high nitrogen treatment than in the other treatments. In fine roots, nitrogen addition promotes the absorption of nitrogen and phosphorus and their stoichiometric ratio, while reducing the content of nonstructural carbohydrates. The content of nonstructural carbohydrates in the small-diameter roots (< 1 mm in diamter) in each nitrogen treatment group was lower than that in the large-diameter roots. Correlation analysis showed that soil carbon and nitrogen were positively correlated with fine root biomass and specific root length and negatively correlated with the nonstructural carbohydrates. Our findings demonstrate that medium nitrogen addition is conducive to the development of fine root morphology, while excessive nitrogen can suppress the growth of root systems.
Kerogen nanoscale structure and CO2 adsorption in shale micropores
Authors: Gonciaruk Aleksandra , Hall Matthew R. , Fay Michael W. , Parmenter Christopher D. J. , Vane Christopher H. , Khlobystov Andrei N. , Ripepi Nino
Published: February 2021

Gas storage and recovery processes in shales critically depend on nano-scale porosity and chemical composition, but information about the nanoscale pore geometry and connectivity of kerogen, insoluble organic shale matter, is largely unavailable. Using adsorption microcalorimetry, we show that once strong adsorption sites within nanoscale network are taken, gas adsorption even at very low pressure is governed by pore width rather than chemical composition. A combination of focused ion beam with scanning electron microscopy and transmission electron microscopy reveal the nanoscale structure of kerogen includes not only the ubiquitous amorphous phase but also highly graphitized sheets, fiber- and onion-like structures creating nanoscale voids accessible for gas sorption. Nanoscale structures bridge the current gap between molecular size and macropore scale in existing models for kerogen, thus allowing accurate prediction of gas sorption, storage and diffusion properties in shales.
Five animal phyla in glacier ice reveal unprecedented biodiversity in New Zealand's Southern Alps
Authors: Shain Daniel H. , Novis Philip M. , Cridge Andrew G. , Zawierucha Krzysztof , Geneva Anthony J. , Dearden Peter K.
Published: February 2021

Glacier ice is an extreme environment in which most animals cannot survive. Here we report the colonization of high elevation, climate-threatened glaciers along New Zealand’s southwestern coast by species of Arthropoda, Nematoda, Platyhelminthes, Rotifera and Tardigrada. Based on DNA barcoding and haplotype-inferred evidence for deep genetic variability, at least 12 undescribed species are reported, some of which have persisted in this niche habitat throughout the Pleistocene. These findings identify not only an atypical biodiversity hotspot but also highlight the adaptive plasticity of microinvertebrate Animalia.
Theory of the sp–d coupling of transition metal impurities with free carriers in ZnO
Authors: Ciechan Anna , Bogusławski Piotr
Published: February 2021

The $$s,p{-}d$$

s
,
p
-
d

exchange coupling between the spins of band carriers and of transition metal (TM) dopants ranging from Ti to Cu in ZnO is studied within the density functional theory. The $$+U$$

+
U

corrections are included to reproduce the experimental ZnO band gap and the dopant levels. The p–d coupling reveals unexpectedly complex features. In particular, (i) the p–d coupling constants $$N_0\beta$$

N
0

β

vary about 10 times when going from V to Ni, (ii) not only the value but also the sign of $$N_0\beta$$

N
0

β

depends on the charge state of the dopant, (iii) the p–d coupling with the heavy holes and the light holes is not the same; in the case of Fe, Co and Ni, $$N_0\beta$$

N
0

β

s for the two subbands can differ twice, and for Cu the opposite sign of the coupling is found for light and heavy holes. The main features of the p–d coupling are determined by the p–d hybridization between the d(TM) and p(O) orbitals. In contrast, the s–d coupling constant $$N_0\alpha$$

N
0

α

is almost the same for all TM ions, and does not depend on the charge state of the dopant. The TM-induced spin polarization of the p(O) orbitals contributes to the s–d coupling, enhancing $$N_0\alpha$$

N
0

α

.
Biochemical aspects of seeds from Cannabis sativa L. plants grown in a mountain environment
Authors: Cattaneo Chiara , Givonetti Annalisa , Leoni Valeria , Guerrieri Nicoletta , Manfredi Marcello , Giorgi Annamaria , Cavaletto Maria
Published: February 2021

Cannabis sativa L. (hemp) is a versatile plant which can adapt to various environmental conditions. Hempseeds provide high quality lipids, mainly represented by polyunsaturated acids, and highly digestible proteins rich of essential aminoacids. Hempseed composition can vary according to plant genotype, but other factors such as agronomic and climatic conditions can affect the presence of nutraceutic compounds. In this research, seeds from two cultivars of C. sativa (Futura 75 and Finola) grown in a mountain environment of the Italian Alps were analyzed. The main purpose of this study was to investigate changes in the protein profile of seeds obtained from such environments, using two methods (sequential and total proteins) for protein extraction and two analytical approaches SDS-PAGE and 2D-gel electrophoresis, followed by protein identification by mass spectrometry. The fatty acids profile and carotenoids content were also analysed. Mountain environments mainly affected fatty acid and protein profiles of Finola seeds. These changes were not predictable by the sole comparison of certified seeds from Futura 75 and Finola cultivars. The fatty acid profile confirmed a high PUFA content in both cultivars from mountain area, while protein analysis revealed a decrease in the protein content of Finola seeds from the experimental fields.
Protective role of Chlorella vulgaris with Thiamine against Paracetamol induced toxic effects on haematological, biochemical, oxidative stress parameters and histopathological changes in Wistar rats
Authors: Latif Amera Abd El , Assar Doaa H. , Elkaw Ebtihal M. , Hamza Hanafy A. , Alkhalifah Dalal Hussien M. , Hozzein Wael N. , Hamouda Ragaa A.
Published: February 2021

Paracetamol is extensively consumed as an analgesic and antipyretic drug, but at a high dose level, it leads to deleterious side effects, such as hepatic and nephrotoxicity. This research aimed to estimate the prophylactic efficacy of Chlorella vulgaris and/or thiamine against paracetamol (P) induced hepatorenal and cardiac toxicity. Forty-eight female Wistar rats were randomly divided into eight equal groups (n = 6 rats). Group 1, normal control group. Group 2, Paracetamol group. Groups 3, 4 and 5 were treated with Silymarin drug, Chlorella vulgaris alga, Chlorella vulgaris alga supplemented with thiamine, respectively daily for 7 successive days, then all were administered Paracetamol (2gm/kg. bwt.). While, Groups 6, 7 and 8 were treated by Silymarin, Chlorella vulgaris alga, Chlorella vulgaris supplemented with thiamine, respectively daily for 7 successive days without paracetamol administration. Our results clarified that Paracetamol toxicity caused significant adverse effects on hematological, serum biochemical parameters, and oxidant -antioxidant status as well as histopathological picture of heart, liver, and kidney. However, in the Paracetamol intoxicated groups pretreatment either with Chlorella vulgaris alone or plus thiamine successfully improved the undesirable deleterious effects of paracetamol, and restored almost all variables to near their control levels. This study has finished to that oxidative stress participates in the pathogenesis of paracetamol-induced toxicity in rats and using Chlorella vulgaris alga either alone or plus thiamine alongside their health benefits can protect against oxidative harmful effects induced by paracetamol through their free radical scavenging and powerful antioxidant effects, and they can be used as propylactic agents against paracetamol-induced toxicity.
-308G/A polymorphism of tumor necrosis factor alpha (TNF-α) gene and metabolic syndrome susceptibility: a meta-analysis
Authors: Wang Dong , He Liqun , Zhang Xiaotian
Published: February 2021

Many studies tried to assess the relationship between -308G/A polymorphism of tumor necrosis factor alpha (TNF-α) gene and risk of metabolic syndrome (MS), but their results were contradictory. This meta-analysis aimed to precisely evaluate this association. A systematic literature search was performed in Pubmed database and WanFang Med Online, STATA software 14.0 was used for the meta-analysis. Eleven independent studies containing 3277 cases and 3312 controls were included in our meta-analysis. In overall analysis, significant association was found between -308G/A polymorphism of TNF-α and MS in both allele model (OR 1.47, 95% CI 1.09–1.98, P 0.013) and dominant model (OR 1.77, 95% CI 1.21–2.58, P 0.003). In the subgroup analysis, the A allele was associated with increased risk of MS in Asia group (allele model: OR 1.82 95% CI 1.31–2.53, P < 0.001; dominant model: OR 2.30, 95% CI 1.64–3.21 P < 0.001; homozygous model: OR 2.29, 95% CI 1.31–4.01, P 0.004), and decreased risk of MS in Europe group (dominant model: OR 0.83, 95% CI 0.70–0.99, P < 0.001; recessive model: OR 0.51, 95% CI 0.28–0.92, P 0.025; homozygous model: OR 0.49 95% CI 0.27–0.89, P 0.02). The A allele also appeared to linked to increased risk of MS in CDS group and IDF groups. No significant association was observed in NCEPATPIII group. Our results suggested that -308G/A of TNF-α gene was a risk factor for MS, but it may played different roles in different ethnics, further studies with larger sample size and more other ethnics should be performed to confirm our conclusions.
Point-of-care testing of plasma free hemoglobin and hematocrit for mechanical circulatory support
Authors: Shin Dong Ah , Lee Jung Chan , Shin Heean , Cho Young-Jae , Kim Hee Chan
Published: February 2021

Hematological analysis is essential for patients who are supported by a mechanical circulatory support (MCS). The laboratory methods used to analyze blood components are conventional and accurate, but they require a mandatory turn-around-time for laboratory results, and because of toxic substances, can also be hazardous to analysis workers. Here, a simple and rapid point-of-care device is developed for the measurement of plasma free hemoglobin (PFHb) and hematocrit (Hct), based on colorimetry. The device consists of camera module, minimized centrifuge system, and the custom software that includes the motor control algorithm for the centrifuge system, and the image processing algorithm for measuring the color components of blood from the images. We show that our device measured PFHb with a detection limit of 0.75 mg/dL in the range of (0–100) mg/dL, and Hct with a detection limit of 2.14% in the range of (20–50)%. Our device had a high correlation with the measurement method generally used in clinical laboratories (PFHb R = 0.999, Hct R = 0.739), and the quantitative analysis resulted in precision of 1.44 mg/dL for PFHb value of 14.5 mg/dL, 1.36 mg/dL for PFHb value of 53 mg/dL, and 1.24% for Hct 30%. Also, the device can be measured without any pre-processing when compared to the clinical laboratory method, so results can be obtained within 5 min (about an 1 h for the clinical laboratory method). Therefore, we conclude that the device can be used for point-of-care measurement of PFHb and Hct for MCS.
Comparison of CURB-65, PSI, and qSOFA for predicting pneumonia mortality in patients with idiopathic pulmonary fibrosis
Authors: Yamazaki Ryo , Nishiyama Osamu , Yoshikawa Kazuya , Saeki Sho , Sano Hiroyuki , Iwanaga Takashi , Tohda Yuji
Published: February 2021

Some patients with idiopathic pulmonary fibrosis (IPF) require hospitalization due to pneumonia. Although predictive scoring tools have been developed and validated for community-acquired pneumonia (CAP), their usefulness in IPF is unknown. The Confusion, Urea, Respiratory Rate, Blood Pressure and Age (CURB-65) score and the Pneumonia Severity Index (PSI) are validated for CAP. The quick Sequential Organ Failure Assessment (qSOFA) is also reported to be useful. The aim of this study was to investigate the ability of these tools to predict pneumonia mortality among hospitalized patients with IPF. A total of 79 patients with IPF and pneumonia were hospitalized for the first time between January 2008 and December 2017. The hospital mortality rate was 15.1%. A univariate logistic regression analysis revealed that the CURB-65 (odds ratio 4.04, 95% confidence interval 1.60–10.2, p = 0.003), PSI (4.00, 1.48–10.7, 0.006), and qSOFA (5.00, 1.44–1.72, 0.01) scores were significantly associated with hospital mortality. There was no statistically significant difference between the three receiver operating characteristic curves (0.712, 0.736, and 0.692, respectively). The CURB-65, PSI, and qSOFA are useful tools for predicting pneumonia mortality among hospitalized patients with IPF. Because of its simplicity, the qSOFA may be most suitable for early assessment.
A Casz1–NuRD complex regulates temporal identity transitions in neural progenitors
Authors: Mattar Pierre , Jolicoeur Christine , Dang Thanh , Shah Sujay , Clark Brian S. , Cayouette Michel
Published: February 2021

Neural progenitor cells undergo identity transitions during development to ensure the generation different types of neurons and glia in the correct sequence and proportions. A number of temporal identity factors that control these transitions in progenitor competence have been identified, but the molecular mechanisms underlying their function remain unclear. Here, we asked how Casz1, the mammalian orthologue of Drosophila castor, regulates competence during retinal development. We show that Casz1 is required to control the transition between neurogenesis and gliogenesis. Using BioID proteomics, we reveal that Casz1 interacts with the nucleosome remodeling and deacetylase (NuRD) complex in retinal cells. Finally, we show that both the NuRD and the polycomb repressor complexes are required for Casz1 to promote the rod fate and suppress gliogenesis. As additional temporal identity factors have been found to interact with the NuRD complex in other contexts, we propose that these factors might act through this common biochemical process to regulate neurogenesis.
A proof-of-concept study of the in-vivo validation of a computational fluid dynamics model of personalized radioembolization
Authors: Antón Raúl , Antoñana Javier , Aramburu Jorge , Ezponda Ana , Prieto Elena , Andonegui Asier , Ortega Julio , Vivas Isabel , Sancho Lidia , Sangro Bruno , Bilbao José Ignacio , Rodríguez-Fraile Macarena
Published: February 2021

Radioembolization (RE) with yttrium-90 (90Y) microspheres, a transcatheter intraarterial therapy for patients with liver cancer, can be modeled computationally. The purpose of this work was to correlate the results obtained with this methodology using in vivo data, so that this computational tool could be used for the optimization of the RE procedure. The hepatic artery three-dimensional (3D) hemodynamics and microsphere distribution during RE were modeled for six 90Y-loaded microsphere infusions in three patients with hepatocellular carcinoma using a commercially available computational fluid dynamics (CFD) software package. The model was built based on in vivo data acquired during the pretreatment stage. The results of the simulations were compared with the in vivo distribution assessed by 90Y PET/CT. Specifically, the microsphere distribution predicted was compared with the actual 90Y activity per liver segment with a commercially available 3D-voxel dosimetry software (PLANET Dose, DOSIsoft). The average difference between the CFD-based and the PET/CT-based activity distribution was 2.36 percentage points for Patient 1, 3.51 percentage points for Patient 2 and 2.02 percentage points for Patient 3. These results suggest that CFD simulations may help to predict 90Y-microsphere distribution after RE and could be used to optimize the RE procedure on a patient-specific basis.
Deep-sea turbulence evolution observed by multiple closely spaced instruments
Authors: Yang Chu-Fang , Chi Wu-Cheng , van Haren Hans
Published: February 2021

Turbulent mixing in the deep ocean is not well understood. The breaking of internal waves on sloped seafloor topography can generate deep-sea turbulence. However, it is difficult to measure turbulence comprehensively due to its multi-scale processes, in addition to flow–flow and flow–topography interactions. Dense, high-resolution spatiotemporal coverage of observations may help shed light on turbulence evolution. Here, we present turbulence observations from four broadband ocean bottom seismometers (OBSs) and a 200-m vertical thermistor string (T-string) in a footprint of 1 × 1 km to characterize turbulence induced by internal waves at a depth of 3000 m on a Pacific continental slope. Correlating the OBS-calculated time derivative of kinetic energy and the T-string-calculated turbulent kinetic energy dissipation rate, we propose that the OBS-detected signals were induced by near-seafloor turbulence. Strong disturbances were detected during a typhoon period, suggesting large-scale inertial waves breaking with upslope transport speeds of 0.2–0.5 m s−1. Disturbances were mostly excited on the downslope side of the array where the internal waves from the Pacific Ocean broke initially and the turbulence oscillated between < 1 km small-scale ridges. Such small-scale topography caused varying turbulence-induced signals due to localized waves breaking. Arrayed OBSs can provide complementary observations to characterize deep-sea turbulence.
Polarimetric imaging microscopy for advanced inspection of vegetal tissues
Authors: Van Eeckhout Albert , Garcia-Caurel Enrique , Garnatje Teresa , Escalera Juan Carlos , Durfort Mercè , Vidal Josep , Gil José J. , Campos Juan , Lizana Angel
Published: February 2021

Optical microscopy techniques for plant inspection benefit from the fact that at least one of the multiple properties of light (intensity, phase, wavelength, polarization) may be modified by vegetal tissues. Paradoxically, polarimetric microscopy although being a mature technique in biophotonics, is not so commonly used in botany. Importantly, only specific polarimetric observables, as birefringence or dichroism, have some presence in botany studies, and other relevant metrics, as those based on depolarization, are underused. We present a versatile method, based on a representative selection of polarimetric observables, to obtain and to analyse images of plants which bring significant information about their structure and/or the spatial organization of their constituents (cells, organelles, among other structures). We provide a thorough analysis of polarimetric microscopy images of sections of plant leaves which are compared with those obtained by other commonly used microscopy techniques in plant biology. Our results show the interest of polarimetric microscopy for plant inspection, as it is non-destructive technique, highly competitive in economical and time consumption, and providing advantages compared to standard non-polarizing techniques.
Calculating the optimal hematocrit under the constraint of constant cardiac power
Authors: Sitina Michal , Stark Heiko , Schuster Stefan
Published: February 2021

In humans and higher animals, a trade-off between sufficiently high erythrocyte concentrations to bind oxygen and sufficiently low blood viscosity to allow rapid blood flow has been achieved during evolution. Optimal hematocrit theory has been successful in predicting hematocrit (HCT) values of about 0.3–0.5, in very good agreement with the normal values observed for humans and many animal species. However, according to those calculations, the optimal value should be independent of the mechanical load of the body. This is in contradiction to the exertional increase in HCT observed in some animals called natural blood dopers and to the illegal practice of blood boosting in high-performance sports. Here, we present a novel calculation to predict the optimal HCT value under the constraint of constant cardiac power and compare it to the optimal value obtained for constant driving pressure. We show that the optimal HCT under constant power ranges from 0.5 to 0.7, in agreement with observed values in natural blood dopers at exertion. We use this result to explain the tendency to better exertional performance at an increased HCT.
Delayed mortality, resistance and the sweet spot, as the good, the bad and the ugly in phosphine use
Authors: Lampiri Evagelia , Agrafioti Paraskevi , Athanassiou Christos G.
Published: February 2021

Phosphine is the most commonly used gas for fumigation for durable commodities globally, but there is still inadequate information regarding its efficacy in conjunction with proper concentration monitoring. In a series of bioassays, insect mortality after specific exposure intervals to phosphine in selected species was examined, as well as the appearance of the so called "sweet spot". The species that were tested were: Oryzaephilus surinamensis (L.), Tribolium castaneum (Herbst), Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) with populations that had different levels of phosphine resistance. Evaluation was conducted by using the Phosphine Tolerance Test (PTT), with exposure of the adult stage for 15, 30, 60, 90, 150 and 300 min at 3000 ppm. At the end of these intervals (separate bioassays for each time interval), the insects were transferred to Petri dishes, in which recovery was recorded at different time intervals (2 h, 1, 2 and 7 days). The majority of susceptible populations of all species were instantly immobilized even in the shortest exposure period (15 min), in contrast with resistant populations that were active even after 300 min. After exposure to phosphine, populations and exposure time affected mortality of susceptible populations, whereas resistant populations recovered regardless of species and exposure time. Additional bioassays at the concentrations of 500, 1000, 2000 and 3000 ppm for 1, 3, 5, 20, 30 and 40 h showed the presence of the "sweet spot", i.e., decrease of mortality with the increase of concentration. In fact, for most of the tested species, the "sweet spot" appeared in 1000 and 2000 ppm at a 5-h exposure time, regardless of the level of resistance to phosphine. This observation is particularly important both in terms of the assessment of resistance and in the context of non-linear recovery at elevated concentrations, indicating the occurrence of strong hormetic reversals in phosphine efficacy.
Real world effectiveness and tolerability of candesartan in the treatment of migraine: a retrospective cohort study
Authors: Sánchez-Rodríguez Carmen , Sierra Álvaro , Planchuelo-Gómez Álvaro , Martínez-Pías Enrique , Guerrero Ángel L. , García-Azorín David
Published: February 2021

To date, two randomized, controlled studies support the use of candesartan for migraine prophylaxis but with limited external validity. We aim to evaluate the effectiveness and tolerability of candesartan in clinical practice and to explore predictors of patient response. Retrospective cohort study including all patients with migraine who received candesartan between April 2008-February 2019. The primary endpoint was the number of monthly headache days during weeks 8–12 of treatment compared to baseline. Additionally, we evaluated the frequency during weeks 20–24. We analysed the percentage of patients with 50% and 75% response rates and the retention rates after three and 6 months of treatment. 120/4121 patients were eligible, aged 45.9 [11.5]; 100 (83.3%) female. Eighty-four patients (70%) had chronic migraine and 53 (42.7%) had medication-overuse headache. The median number of prior prophylactics was 3 (Inter-quartile range 2–5). At baseline, patients had 20.5 ± 8.5 headache days per month, decreasing 4.3 ± 8.4 days by 3 months (weeks 12–16) and by 4.7 ± 8.7 days by 6 months (paired Student’s t-test,p < 0.001). The percentage of patients with a 50% response was 32.5% at 3 months and 31.7% at 6 months, while the retention rate was 85.0% and 58.3%. The number of prior treatments (Odds ratio 0.79, 95% CI 0.64–0.97) and the presence of daily headache (Odds ratio 0.39, 95% CI 0.16–0.97) were associated with a lower probability of response. Candesartan showed beneficial effects in the preventive treatment of migraine in clinical practice, including patients with chronic migraine, medication-overuse headache and resistance to prior prophylactics.
Macrophage-derived EDA-A2 inhibits intestinal stem cells by targeting miR-494/EDA2R/β-catenin signaling in mice
Authors: Song Lele , Chang Renxu , Sun Xia , Lu Liying , Gao Han , Lu Huiying , Lin Ritian , Xu Xiaorong , Liu Zhanju , Zhan Lixing
Published: February 2021

The mucosa microenvironment is critical for intestinal stem cell self-renewal and reconstruction of the epithelial barrier in inflammatory bowel disease (IBD), where the mechanisms underlying cross-talk between intestinal crypts and the microenvironment remain unclear. Here, we firstly identified miR-494-3p as an important protector in colitis. miR-494-3p levels were decreased and negatively correlated with the severity in human IBD samples, as well as in colitis mice. In colitis crypts, a notable cytokine–cytokine receptor, miR-494-3p-targeted EDA2R and the ligand EDA-A2, suppressed colonic stemness and epithelial repair by inhibiting β-catenin/c-Myc. In differentiated IECs, miR-494-3p inhibits macrophage recruitment, M1 activation and EDA-A2 secretion by targeting IKKβ/NF-κB in colitis. A miR-494-3p agomir system notably ameliorated the severity of colonic colitis in vivo. Collectively, our findings uncover a miR-494-3p-mediated cross-talk mechanism by which macrophage-induced intestinal stem cell impairment aggravates intestinal inflammation.
Analysis of SARS-CoV-2 mutations in the United States suggests presence of four substrains and novel variants
Authors: Wang Rui , Chen Jiahui , Gao Kaifu , Hozumi Yuta , Yin Changchuan , Wei Guo-Wei
Published: February 2021

SARS-CoV-2 has been mutating since it was first sequenced in early January 2020. Here, we analyze 45,494 complete SARS-CoV-2 geneome sequences in the world to understand their mutations. Among them, 12,754 sequences are from the United States. Our analysis suggests the presence of four substrains and eleven top mutations in the United States. These eleven top mutations belong to 3 disconnected groups. The first and second groups consisting of 5 and 8 concurrent mutations are prevailing, while the other group with three concurrent mutations gradually fades out. Moreover, we reveal that female immune systems are more active than those of males in responding to SARS-CoV-2 infections. One of the top mutations, 27964C > T-(S24L) on ORF8, has an unusually strong gender dependence. Based on the analysis of all mutations on the spike protein, we uncover that two of four SARS-CoV-2 substrains in the United States become potentially more infectious.
Hand-portable HPLC with broadband spectral detection enables analysis of complex polycyclic aromatic hydrocarbon mixtures
Authors: Chatzimichail Stelios , Rahimi Faraz , Saifuddin Aliyah , Surman Andrew J. , Taylor-Robinson Simon D. , Salehi-Reyhani Ali
Published: February 2021

Polycyclic aromatic hydrocarbons (PAHs) are considered priority hazardous substances due to their carcinogenic activity and risk to public health. Strict regulations are in place limiting their release into the environment, but enforcement is hampered by a lack of adequate field-testing procedure, instead relying on sending samples to centralised analytical facilities. Reliably monitoring levels of PAHs in the field is a challenge, owing to the lack of field-deployable analytical methods able to separate, identify, and quantify the complex mixtures in which PAHs are typically observed. Here, we report the development of a hand-portable system based on high-performance liquid chromatography incorporating a spectrally wide absorption detector, capable of fingerprinting PAHs based on their characteristic spectral absorption profiles: identifying 100% of the 24 PAHs tested, including full coverage of the United States Environmental Protection Agency priority pollutant list. We report unsupervised methods to exploit these new capabilities for feature detection and identification, robust enough to detect and classify co-eluting and hidden peaks. Identification is fully independent of their characteristic retention times, mitigating matrix effects which can preclude reliable determination of these analytes in challenging samples. We anticipate the platform to enable more sophisticated analytical measurements, supporting real-time decision making in the field.
Quantum magnetic monopole condensate
Authors: Diamantini M. C. , Trugenberger C. A. , Vinokur V. M.
Published: February 2021

Despite decades-long efforts, magnetic monopoles were never found as elementary particles. Monopoles and associated currents were directly measured in experiments and identified as topological quasiparticle excitations in emergent condensed matter systems. These monopoles and the related electric-magnetic symmetry were restricted to classical electrodynamics, with monopoles behaving as classical particles. Here we show that the electric-magnetic symmetry is most fundamental and extends to full quantum behavior. We demonstrate that at low temperatures magnetic monopoles can form a quantum Bose condensate dual to the charge Cooper pair condensate in superconductors. The monopole Bose condensate manifests as a superinsulating state with infinite resistance, dual to superconductivity. The monopole supercurrents result in the electric analog of the Meissner effect and lead to linear confinement of the Cooper pairs by Polyakov electric strings in analogy to quarks in hadrons.
Experimental test of Babinet's principle in matter-wave diffraction
Authors: Kim Lee Yeong , Lee Ju Hyeon , Kim Yun-Tae , Park Sanghwan , Lee Chang Young , Schöllkopf Wieland , Zhao Bum Suk
Published: February 2021

We report on an experimental test of Babinet's principle in quantum reflection of an atom beam from diffraction gratings.
In situ isotopic analysis of uranium using a new data acquisition protocol for 1013 ohm Faraday amplifiers
Authors: Yamamoto Kota , Asanuma Hisashi , Takahashi Hiroaki , Hirata Takafumi
Published: February 2021

New data reduction method for isotopic measurements using high-gain Faraday amplifiers enables precise uranium isotopic analysis even from transient signals.
Using design of experiment to obtain a systematic understanding of the effect of synthesis parameters on the properties of perovskite nanocrystals
Authors: Baker Robert W. , Forfar Laura , Liang Xinxing , Cameron Petra J.
Published: February 2021

Design of experiments was used to systematically investigate the synthesis of MAPbI3 nanoparticles in a flow reactor. By controlling the solvents and the ligands, we were able to tune the MAPbI3 photoluminescence peak between 614 and 737 nm.
Iron-catalyzed tandem oxidative coupling and acetal hydrolysis reaction to prepare formylated benzothiazoles and isoquinolines
Authors: Wu Yue , Guo Peng , Chen Long , Duan Weijie , Yang Zengzhuan , Wang Tao , Chen Ting , Xiong Fei
Published: February 2021

The aldehyde group is one of the most versatile intermediates in synthetic chemistry, and the introduction of an aldehyde group into heteroarenes is important for the transformation of molecular structure.
Hapten synthesis and antibody production for the development of a paper immunosensor for lean meat powder zilpaterol
Authors: Xu Xiaoxin , Sun Li , Wang Zhongxing , Guo Lingling , Xu Xinxin , Wu Aihong , Kuang Hua , Song Shanshan , Xu Chuanlai
Published: February 2021

An anti-zilpaterol mAb with an IC50 of 0.31 ng mL−1 and a limit of detection (LOD) of 0.02 ng mL−1 has been developed. For semi-quantitative detection in pork samples, the visual LOD is 0.5 ng mL−1 and the cut-off value is 5 ng mL−1.
Fullerene translocation through peroxidized lipid membranes
Authors: Gul Gulsah , Ileri-Ercan Nazar
Published: February 2021

The translocation of fullerenes and their polar conjugates (Janus) is investigated across model membranes and their different peroxidized forms.
Correction: Speedy one-pot electrochemical synthesis of giant octahedrons from in situ generated pyrrolidinyl PAMAM dendrimer
Authors: Singhania Anup , Dutta Mrinal , Saha Supriya , Sahoo Pathik , Bora Bharati , Ghosh Subrata , Fujita Daisuke , Bandyopadhyay Anirban
Published: February 2021

Correction for ‘Speedy one-pot electrochemical synthesis of giant octahedrons from in situ generated pyrrolidinyl PAMAM dendrimer’ by Anup Singhania et al., Soft Matter, 2020, 16, 9140–9146, DOI: 10.1039/D0SM00819B.
An axial passive magnetic bearing using three PM rings
Authors: Marignetti Fabrizio , AlizadehTir Milad , Mirimani Seyyed Mehdi
Published: February 2021

The results of numerical and experimental analysis of passive magnetic bearings are presented. The proposed structure is composed of three radially stacked ring‐shaped permanent magnets. The improvements of stiffness and load capacity are proven in comparison to the classical passive magnetic bearing composed of two rings. A preliminary sensitivity analysis is carried out by means of the 2‐dimensional finite element method (FEM) modelling, which is used to provide the initial points for the stochastic optimisation and also to define the best fitness and penalty functions. Finally, the 2‐dimensional FEM is used to compare the force density and the cost of the proposed structure to those of the classical passive magnetic bearing composed of two rings. The optimised structure was manufactured and validated by experimental measurements. The proposed passive magnetic bearing exerts greater axial force and stiffness than similar structures.
Inter‐circuit fault location algorithm in generalized unified power flow controller‐compensated double‐circuit transmission lines based on synchronous current and voltage phasors of line terminals
Authors: Abasi Mahyar , Joorabian Mahmood , Saffarian Alireza , Seifossadat Seyed Ghodratollah
Published: February 2021

An accurate inter‐circuit fault location algorithm for double‐circuit transmission lines compensated by a generalized unified power flow controller based on phasor analysis is presented. The proposed algorithm utilizes synchronous currents and voltages of the buses on both sides of the line to accurately calculate the fault location. Using the equations of sequence component circuits, the algorithm calculates voltage and current of the fault point on both circuits. Then, using boundary conditions equations for 98 types of inter‐circuit fault on the double‐circuit transmission lines, the accurate location of the fault is obtained. The number of boundary conditions equations varies depending on the type of faulty phases of the two circuits and the number of unknowns in the current and voltage equations of the fault point. The calculation of these boundary equations are also described. The results presented in the simulation section verify the validity and accurate performance of the proposed algorithm under different fault conditions.
Detection of symbol‐asynchronous uplink NOMA with imperfect time offsets
Authors: Liu Jingmin , Li Ying , Sun Yue
Published: February 2021

A symbol‐asynchronous uplink non‐orthogonal multiple access (NOMA) model is considered, where K users transmit codewords to a common receiver according to their local clocks. As the complicated user location and the dynamic transmission environment, the exact time offsets of users are not always available at the base station (BS). To ensure the efficiency of the system, linear minimum mean square error algorithm and partial message passing (P‐MP) algorithm are designed based on iterative detection. The signal to interference plus noise ratio is also applied to analysis the effect of estimated time offsets on the P‐MP algorithm. Then simulation results show that when the variance of estimation error is , the symbol‐asynchronous NOMA systems with imperfect time offsets can achieve the same or even better bit error rate performance than the NOMA system.
Mean‐based reciprocity calibration in TDD massive MIMO system
Authors: Kumar Varun , Patra Sarat Kumar , Singh Poonam
Published: February 2021

Non‐reciprocity limits the potential of time division duplexing (TDD) massive multiple‐input and multiple‐output (MIMO) systems. Due to the reciprocal channel, there is no need for downlink (DL) pilot transmission implies computational complexity reduction and saving precious time resources. In this study, the DL channel matrix is estimated using the uplink channel matrix by a novel reciprocity calibration technique. Non‐reciprocity arises due to the hardware mismatch (HM) across the base station (BS) and the user terminal (UT)/both. Its detrimental effect causes amplitude and phase impairment in the downlink signal transmission. Since a massive MIMO network has a large number of antenna elements across the BS, hence the instantaneous HM coefficient cannot be determined accurately. For solving such a problem, the authors use the statistical response of the hardware unit. Considering a complex Gaussian hardware response across each antenna terminal, the probability density function (PDF) of amplitude and phase mismatch is derived. They also derive the joint PDF of amplitude and phase mismatch, considering the HM. Simulation results address the sensitivity and complexity for evaluating the sum‐rate capacity under three linear precoders (matched filter, regularized zero‐forcing, and zero‐forcing), which validate their effectiveness in this scenario.
Supporting legacy and RF‐energy harvesting devices in multi‐cells OFDMA networks
Authors: Sarwar Muhammad Zeeshan , Chin Kwan‐Wu
Published: February 2021

A multi‐cell network that uses orthogonal frequency division multiplexing access (OFDMA) is studied here. Unlike prior works, the proposed network consists of both (i) legacy data users that do not have energy harvesting capability and have a minimum data rate requirement and (ii) radio frequency (RF)‐energy harvesting devices with a minimum energy requirement. It studies sub‐band allocation to users and transmits power allocation at base stations. The authors formulate a mixed‐integer non‐linear program and also present two heuristics to assign sub‐band to base stations. Numerical results show that RF energy harvesting devices will not affect network capacity if legacy data users require a high data rate. In addition, the results obtained from the two proposed heuristics are 95% of the optimal solution.
Multi‐tier MEC offloading strategy based on dynamic channel characteristics
Authors: Li Nana , Yang Shouyi , Wang Zhaoyang , Hao Wanming , Zhu Yifan
Published: February 2021

Comparing with the cloud computing, mobile edge computing (MEC) can further decrease the latency and improve the stability of the networks. However, it is challenging for the edge servers to deal with the large computation task due to the limited computing capacity. In this study, we design a novel three‐layer network architecture consisting of mobile devices, edge cloudlets, and helper cloudlets, where the computing data can be partially processed at the edge cloudlet and helper cloudlet. Based on this, a joint communication, offloading, and computation resource allocation problem is formulated to minimise the computation cost and energy consumption. Due to its difficulty to directly solve the formulated problem, we first propose an offloading scheme to obtain the closed‐form solutions for the optimal offloading data size. Next, we decompose the optimisation problem into two subproblems: (i) for the cloud execution, we dynamically adjust the data transmission rate according to the stochastic channel condition, (ii) for the mobile execution, the energy consumption can be further reduced by applying the dynamic voltage and frequency scaling technique. Finally, the numerical results demonstrate the efficiency of the proposed scheme, and show the performance gains in terms of delay, computation cost and energy consumption.
Spectral efficiency of a non‐orthogonal FH‐CDMA system
Authors: de Miranda Marques Daniel Hindemburg , Sharma Manish
Published: February 2021

Fast frequency hopping code division multiple access (FH‐CDMA) is a low complexity option for multiuser communication in fast, frequency selective fading channels such as in mobile mmWave communications. The original, orthogonal FH‐CDMA has low spectral efficiency and up to now lacks a non‐orthogonal version. In this work, a soft input soft output, non‐orthogonal multiuser detector is designed using factor graphs. Extrinsic Information Transfer (EXIT) chart analysis of this detector allows determination of which multiple access code length maximises system spectral efficiency. Results show that when the access code length is reduced to an ideal length, spectral efficiency is maximised. Another conclusion is that maximum spectral efficiency is similar in value to a system with no multiple access method.
Robust underlay cognitive network download beamforming in multiple users, multiple groups multicell scenario
Authors: Al‐Asadi Ahmed , Al‐Amidie Muthana , Alwane Saddam K. , Albehadili Hayder M. , McGarvey Ronald G. , Islam and Naz E.
Published: February 2021

Achieving high quality of service (QOS) at the end‐users while maintaining the low interference power at the primary users is the main goal in underlay cognitive radio networks. This goal becomes a more difficult task in the designing of beamforming vectors where all channels state information (CSIs) in the secondary network, as well as the interference CSIs, are uncertain. This task is addressed in this study using an iterative optimization technique. In this technique, the original CSI problem, which is difficult to solve as a single optimization problem, is instead separated into two sub‐problems. The first subproblem is the interference power problem, which can be solved either sub‐optimally or optimally using Lagrange duality. The second sub‐problem is the QOS problem, which can be solved either sub‐optimally or robustly using non‐monotone spectral projected gradient method. The two sub‐problem solutions are then recombined into a single problem to extract beamforming vectors. Two methods are invoked to extract the beamforming vectors: either the successive convex approximation (SCA) method or the bisection search method. Theoretical analysis and simulation results indicate that the two methods can offer a tradeoff between better QOS (using bisection search method) or less computational complexity (using SCA method)
Coverage and rate analysis for 5G‐heterogeneous network: β‐Ginibre point process
Authors: Amine Ouamri Mohamed
Published: February 2021

Stochastic geometry is emerging as tractable solution and attractive approach to evaluate the performance of 5G heterogeneous network (5G‐Hetnet) such as coverage, outage and rate probability. The base stations (BSs) and fading distribution in 5G‐Hetnet are an almost ubiquitous assumption for analytical study, requiring flexible and scalable approaches. However, the β‐Ginibre point process (β‐GPP) has been proposed as a new method to model wireless network. This study provides a general framework to analyse downlink mmWave cellular network with Nakagami‐m fading and directional beamforming. First, cell association scheme in both line‐of‐site and non‐line‐of‐site is considered based on the strongest average received power. After deriving cell association probability between user equipment and BS, the computationally coverage probability expression is obtained depending on signal‐to‐interference‐plus‐noise ratio. Furthermore, the impact of biasing factor on rate coverage probability is investigated. Finally, considering inter‐cell‐interference coordination, most performances metrics will be re‐evaluated to determine their influence on the network. Recommended approaches produce satisfactory results when biasing factor and antenna beamforming are used.
Achievable rate analysis and maximisation for the SWIPT‐based half‐duplex quantise‐and‐forward cooperation in IoT networks
Authors: Zhang Shunwai , Shi Xiaoxiao , Song Rongfang , Yang Fengfan
Published: February 2021

To achieve reliable and green communication in the internet of things (IoT) networks, the authors extend the traditional half‐duplex quantise‐and‐forward (QF) cooperation into the simultaneous wireless information and power transfer (SWIPT) regime. This study investigates the achievable rate of the SWIPT‐based half‐duplex QF cooperation with the channel state information available only at the receivers. The source and destination are provided by the external power supply and the relay simultaneously implements the information transmission and the energy harvesting by SWIPT technology with the power‐splitting protocol. The achievable rate of the proposed system over the additive white Gaussian noise channels is analysed and further maximised by optimising the power‐splitting factor. Furthermore, the expected rate of the proposed system over the slow‐fading channels is analysed. Theoretical analysis and simulation results show that the achievable rate or expected rate of the SWIPT‐based QF cooperation is obviously superior to that of the SWIPT‐based amplify‐and‐forward or SWIPT‐based decode‐and‐forward cooperation. Meanwhile, the SWIPT‐based QF cooperation can achieve similar performance to the traditional QF cooperation when the external power supply at the relay is not provided.
Computation offloading time optimisation via Q‐learning in opportunistic edge computing
Authors: Yang Guisong , Hou Ling , Cheng Hao , He Xingyu , He Daojing , Chan Sammy
Published: February 2021

The emergence of computation offloading can meet the real‐time requirements of computing tasks with intensive computing demands. In this study, the authors use opportunistic communication to construct a network framework for opportunistic edge computing (OEC) to perform computation offloading. Specifically, OEC forms a computing resource pool near the edge servers in the edge layer by gathering idle computing resources. Firstly, the state of the system is defined by the attributes of the computing task, the execution location of the computing task and the location of the terminal device in OEC. Then the computation offloading time is calculated and learned by selecting different offloading nodes. Finally, an optimal offloading node selection strategy based on the Q‐learning algorithm is obtained. Extensive simulations show that the proposed strategy consumes the minimum computation offloading time compared with benchmark algorithms in aspects of the amount of uploaded data, the total number of CPU cycles of the task and the number of computing tasks.