bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas effect for oblique and conical shock waves at high temperature
Authors: Yahiaoui Toufik , Zebbiche Toufik , Allali Abderrazak , Boun-jad Mohamed
Published: October 2020

The work focuses to develop a new numerical calculation program for determining the gas effect at high temperature instead air on the calculation of the oblique and conical shock waves parameters and make applications for various external and internal aerodynamics problems like, the calculation of the suitable intake adaptation parameters, dihedron and cone wave drag, aerodynamic coefficients of a pointed supersonic airfoil and oblique shock reflection without forgetting others no less important like the detonation propulsion and the dust explosion applications, where the high temperature gas effect is very important. All this for future aerodynamics (gas dynamics) like the phenomenon of climate change in the near and far future because of the enlargement progressive of the layer ozone hole which will lead to an increase in the temperature of the ambient medium, and by the environment pollution by the shining of the waste which will cause a new decomposition of gases from the ambient environment. Another interesting application for actual aerodynamics (gas dynamics) is the performance of tests in wind tunnels supplied by a combustion chamber making a reaction of gases giving a gas with new thermodynamics parameters which is not necessarily air. To make a calculation, the selected gases are H2, O2, N2, CO, CO2, H2O, NH3, CH4 and air. All shock parameters depend on the stagnation temperature, upstream Mach number, the thermodynamics of the used gas, dihedron and cone deviation and others parameters. The specific heat at constant pressure varies with the temperature and the selected gas. Gas is still considered as perfect. It is calorically imperfect, and thermally perfect, less than the molecules dissociation threshold. A comparison between the parameters of each gas and air is presented to choose the suitable gas witch giving good performances as required by design parameters instead air.
Robust parallel decision-making in neural circuits with nonlinear inhibition
Authors: Kriener Birgit , Chaudhuri Rishidev , Fiete Ila R.
Published: October 2020

Significance

Animals frequently need to choose the best alternative from a set of possibilities, whether it is which direction to swim in or which food source to favor. How long should a network of neurons take to choose the best of

N

options? Theoretical results suggest that the optimal time grows as

log

(

N

)

, if the values of each option are imperfectly perceived. However, standard self-terminating neural network models of decision-making cannot achieve this optimal behavior. We show how using certain additional nonlinear response properties in neurons, which are ignored in standard models, results in a decision-making architecture that both achieves the optimal scaling of decision time and accounts for multiple experimentally observed features of neural decision-making.
Dynamic phase transitions in freestanding polymer thin films
Authors: Ivancic Robert J. S. , Riggleman Robert A.
Published: October 2020

Significance

As a bulk supercooled liquid approaches the glass transition temperature, spatiotemporal fluctuations in dynamics increase by orders of magnitude. While this effect is fundamental to the glass transition, few have studied how confinement affects this dynamic heterogeneity. Here, we examine this effect in thin films through the lens of the dynamic phase transition from high- to low-mobility dynamic states in a set of model freestanding thin films. We find that changes in this dynamic transition are similar to deviations in thermodynamic transitions under confinement due to capillary condensation. Furthermore, these changes are reminiscent of several atypical features of the glass transition observed in ultrathin film experiments, suggesting a possible link between our simulations and experiments.
CO
2
-leakage-driven diffusiophoresis causes spontaneous accumulation of charged materials in channel flow
Authors: Shim Suin , Stone Howard A.
Published: October 2020

Significance

Particle-laden flow is ubiquitous in physiological and diagnostic systems, where usually the particles (e.g., colloidal particles, cells, macromolecules, etc.) gain a nonzero net surface charge when suspended in an aqueous phase. Polydimethylsiloxane (PDMS) has been the most popular material used for microfluidic fabrications for the past two decades. Its high gas permeability is well appreciated, but the possible influence of gas leakage on the motion of charged particles has not been recognized. By systematic experiments and model calculations, we demonstrate that initial (early time) gas leakage through PDMS can create a charge-dependent accumulation of particles in common channel flows by diffusiophoresis and show that the phenomenon can be applied to concentrating and collecting proteins.
The logic of universalization guides moral judgment
Authors: Levine Sydney , Kleiman-Weiner Max , Schulz Laura , Tenenbaum Joshua , Cushman Fiery
Published: October 2020

Significance

Humans have several different ways to decide whether an action is wrong: We might ask whether it causes harm or whether it breaks a rule. Moral psychology attempts to understand the mechanisms that underlie moral judgments. Inspired by theories of “universalization” in moral philosophy, we describe a mechanism that is complementary to existing approaches, demonstrate it in both adults and children, and formalize a precise account of its cognitive mechanisms. Specifically, we show that, when making judgments in novel circumstances, people adopt moral rules that would lead to better consequences if (hypothetically) universalized. Universalization may play a key role in allowing people to construct new moral rules when confronting social dilemmas such as voting and environmental stewardship.
Signatures of a liquid–liquid transition in an ab initio deep neural network model for water
Authors: Gartner Thomas E. , Zhang Linfeng , Piaggi Pablo M. , Car Roberto , Panagiotopoulos Athanassios Z. , Debenedetti Pablo G.
Published: October 2020

Significance

Water is central across much of the physical and biological sciences and exhibits physical properties that are qualitatively distinct from those of most other liquids. Understanding the microscopic basis of water’s peculiar properties remains an active area of research. One intriguing hypothesis is that liquid water can separate into metastable high- and low-density liquid phases at low temperatures and high pressures, and the existence of this liquid–liquid transition could explain many of water’s anomalous properties. We used state-of-the-art approaches in computational quantum chemistry, statistical mechanics, and machine learning and obtained evidence consistent with a liquid–liquid transition, supporting the argument for the existence of this phenomenon in real water.
Ernst Joachim Ungewickell: 1950–2020
Authors: Traub Linton M. , Brodsky Frances M.
Published: October 2020

Linton M. Traub and Frances M. Brodsky discuss the life and achievements of Ernst Ungewickell, who passed away on August 19th.
Gray Platelet Syndrome Presenting With Pancytopenia, Splenomegaly, and Bone Marrow Fibrosis
Authors: Tariq Hamza , Perez Botero Juliana , Higgins Russell A , Medina Edward A
Published: October 2020

Objectives

Gray platelet syndrome (GPS) is a rare platelet storage pool disorder associated with a marked decrease or absence of platelet α-granules and their contents. It is characterized clinically by mild to moderate bleeding; moderate macrothrombocytopenia with large, agranular platelets; splenomegaly; and bone marrow fibrosis. Electron microscopy confirms markedly reduced or absent α-granules in platelets and megakaryocytes. The classic description of GPS is caused by homozygous mutations in NBEAL2 (neurobeachinlike 2).

Methods

A 28-year-old Hispanic man with a history of easy bruising and occasional episodes of epistaxis sought treatment for pancytopenia and splenomegaly. Peripheral blood smear and bone marrow analysis, electron microscopy, and next-generation sequencing were performed.

Results

Large and agranular platelets were present in the peripheral blood. There was bone marrow fibrosis. Electron microscopy of the platelets showed absence of α-granules. Next-generation sequencing revealed a germline apparently homozygous nonsense variant in the NBEAL2 gene: c.5674C>T, p.Gln1892X (p.Q1829X).

Conclusions

The differential diagnosis of GPS includes a myeloid neoplasm such as myelodysplastic syndrome with bone marrow fibrosis. The availability of diagnostic genetic panels for hereditable platelet disorders can assist in the recognition of GPS and other platelet disorders. We also describe a previously unreported pathogenic germline homozygous nonsense variant in the NBEAL2 gene: c.5674C>T, p.Gln1892X (p.Q1829X) in a patient with GPS.
Tracing the footsteps of autophagy in computational biology
Authors: Sarmah Dipanka Tanu , Bairagi Nandadulal , Chatterjee Samrat
Published: October 2020

Autophagy plays a crucial role in maintaining cellular homeostasis through the degradation of unwanted materials like damaged mitochondria and misfolded proteins. However, the contribution of autophagy toward a healthy cell environment is not only limited to the cleaning process. It also assists in protein synthesis when the system lacks the amino acids’ inflow from the extracellular environment due to diet consumptions. Reduction in the autophagy process is associated with diseases like cancer, diabetes, non-alcoholic steatohepatitis, etc., while uncontrolled autophagy may facilitate cell death. We need a better understanding of the autophagy processes and their regulatory mechanisms at various levels (molecules, cells, tissues). This demands a thorough understanding of the system with the help of mathematical and computational tools. The present review illuminates how systems biology approaches are being used for the study of the autophagy process. A comprehensive insight is provided on the application of computational methods involving mathematical modeling and network analysis in the autophagy process. Various mathematical models based on the system of differential equations for studying autophagy are covered here. We have also highlighted the significance of network analysis and machine learning in capturing the core regulatory machinery governing the autophagy process. We explored the available autophagic databases and related resources along with their attributes that are useful in investigating autophagy through computational methods. We conclude the article addressing the potential future perspective in this area, which might provide a more in-depth insight into the dynamics of autophagy.
Is the age of plant communities predicted by the age, stability and soil composition of the underlying landscapes? An investigation of OCBILs
Authors: De Souza Cortez Maria Beatriz , Folk Ryan A , Grady Charles J , Spoelhof Jonathan P , Smith Stephen A , Soltis Douglas E , Soltis Pamela S
Published: October 2020

Old, climatically buffered, infertile landscapes (OCBILs) have been hypothesized to harbour an elevated number of persistent plant lineages and are predicted to occur across different parts of the globe, interspersed with other types of landscapes. We tested whether the mean age of a plant community is associated with occurrence on OCBILs, as predicted by climatic stability and poor soil environments. Using digitized occurrence data for seed plants occurring in Australia (7033 species), sub-Saharan Africa (3990 species) and South America (44 482 species), regions that comprise commonly investigated OCBILs (Southwestern Australian Floristic Region, Greater Cape Floristic Region and campos rupestres), and phylogenies pruned to match the species occurrences, we tested for associations between environmental data (current climate, soil composition, elevation and climatic stability) and two novel metrics developed here that capture the age of a community (mean tip length and mean node height). Our results indicate that plant community ages are influenced by a combination of multiple environmental predictors that vary globally; we did not find statistically strong associations between the environments of OCBIL areas and community age, in contrast to the prediction for these landscapes. The Cape Floristic Region was the only OCBIL that showed a significant, although not strong, overlap with old communities.
In vitro models of the human endometrium: evolution and application for women’s health+
Authors: Fitzgerald Harriet C , Schust Danny J , Spencer Thomas E
Published: October 2020

The endometrium is the inner lining of the uterus that undergoes complex regeneration and differentiation during the human menstrual cycle. The process of endometrial shedding, regeneration, and differentiation is driven by ovarian steroid hormones and prepares the endometrium and intrauterine environment for embryo implantation and pregnancy establishment. Endometrial glands and their secretions are essential for pregnancy establishment, and cross talk between the glandular epithelium and stromal cells appears vital for decidualization and placental development. Despite being crucial, the biology of the human endometrium during pregnancy establishment and most of pregnancy is incomplete, given the ethical and practical limitations of obtaining and studying endometrium from pregnant women. As such, in vitro models of the human endometrium are required to fill significant gaps in understanding endometrial biology. This review is focused on the evolution and development of in vitro three-dimensional models of the human endometrium and provides insight into the challenges and promises of those models to improve women’s reproductive health.
Risk Factors and Outcomes of Antibiotic-resistant Pseudomonas aeruginosa Bloodstream Infection in Adult Patients With Acute Leukemia
Authors: Zhao Yuanqi , Lin Qingsong , Liu Li , Ma Runzhi , Chen Juan , Shen Yuyan , Zhu Guoqing , Jiang Erlie , Mi Yingchang , Han Mingzhe , Wang Jianxiang , Feng Sizhou
Published: October 2020

Background

Pseudomonas aeruginosa (PA) bloodstream infection (BSI) is a common complication in patients with acute leukemia (AL), and the prevalence of antibiotic-resistant strains poses a serious problem. However, there is limited information regarding antibiotic resistance, clinical characteristics, and outcomes of PA BSI in AL patients. This study explored characteristics associated with the clinical outcomes of AL patients with PA BSI and analyzed factors associated with BSI caused by multidrug-resistant (MDR) or carbapenem-resistant strains.

Methods

This single-center retrospective study enrolled hospitalized AL patients who developed PA BSI during January 2014–December 2019. The Kaplan-Meier method was used to plot survival curves. Multivariate logistic regression analyses were also performed.

Results

Of 293 eligible patients with PA BSI, 55 (18.8%) received inappropriate empirical antibiotic therapy within 48 hours of BSI onset, whereas up to 65.8% MDR-PA BSI patients received inappropriate empirical treatment. The 30-day mortality rate was 8.5% for all patients. However, the 30-day mortality rates were 28.9% and 5.5% in MDR-PA BSI and non–MDR-PA BSI patients, respectively (P < .001). On multivariate analysis, previous use of quinolones (odds ratio [OR], 5.851 [95% confidence interval {CI}, 2.638–12.975]) and piperacillin/tazobactam (OR, 2.837 [95% CI, 1.151–6.994]) were independently associated with MDR-PA BSI; and MDR-PA BSI (OR, 7.196 [95% CI, 2.773–18.668]), perianal infection (OR, 4.079 [95% CI, 1.401–11.879]), pulmonary infection (OR, 3.028 [95% CI, 1.231–7.446]), and age ≥55 years (OR, 2.871 [95% CI, 1.057–7.799]) were independent risk factors for 30-day mortality.

Conclusions

MDR increases mortality risk in PA BSI patients, and previous antibiotic exposure is important in MDR-PA BSI development. Rational antibiotic use based on local antimicrobial susceptibility and clinical characteristics can help reduce antibiotic resistance and mortality.
Different drivers, common mechanism; the distribution of a reef fish is restricted by local-scale oxygen and temperature constraints on aerobic metabolism
Authors: Duncan Murray I , James Nicola C , Potts Warren M , Bates Amanda E
Published: October 2020

The distributions of ectothermic marine organisms are limited to temperature ranges and oxygen conditions that support aerobic respiration, quantified within the metabolic index (ϕ) as the ratio of oxygen supply to metabolic oxygen demand. However, the utility of ϕ at local scales and across heterogenous environments is unknown; yet, these scales are often where actionable management decisions are made. Here, we test if ϕ can delimit the entire distribution of marine organisms when calibrated across an appropriate temperature range and at local scales (~10 km) using the endemic reef fish, Chrysoblephus laticeps, which is found in the highly heterogenous temperature and oxygen environment along the South African coastal zone, as a model species. In laboratory experiments, we find a bidirectional (at 12°C) hypoxia tolerance response across the temperature range tested (8 to 24°C), permitting a piecewise calibration of ϕ. We then project this calibrated ϕ model through temperature and oxygen data from a high spatial resolution (11 to 13 km) ocean model for the periods 2005 to 2009 and 2095 to 2099 to quantify various magnitudes of ϕ across space and time paired with complementary C. laticeps occurrence points. Using random forest species distribution models, we quantify a critical ϕ value of 2.78 below which C. laticeps cannot persist and predict current and future distributions of C. laticeps in line with already observed distribution shifts of other South African marine species. Overall, we find that C. laticeps’ distribution is limited by increasing temperatures towards its warm edge but by low oxygen availability towards its cool edge, which is captured within ϕ at fine scales and across heterogenous oxygen and temperature combinations. Our results support the application of ϕ for generating local- and regional-scale predictions of climate change effects on organisms that can inform local conservation management decisions.
The Temporal Dynamics of Two Morpho Fabricius, 1807 Species (Lepidoptera: Nymphalidae) are Affected Differently by Fire in the Brazilian Savanna
Authors: Nascimento André Rangel , Malinov Ivan Konstantinov , Freire Geraldo , Freitas André Victor Lucci , Diniz Ivone Rezende
Published: October 2020

Fire is one of the main disturbance agents globally and one of the main threats on the Brazilian cerrado (Neotropical savanna), acting as environmental filter for species selection. Individuals of Morpho helenor achillides (C. Felder and R. Felder, 1867) and M. menelaus coeruleus (Perry, 1810) were captured weekly using entomological nets and fruit-baited traps over a 36-mo period (from May 2005 to April 2008). The present study analyzed the impact of a fire event in both the above species, showing that they present different responses to this disturbance. Morpho helenor was persistent as adults during the dry season, which could fly away from the flames to neighbor unburned areas and return after dry-season bushfires. Conversely, Morpho menelaus persists only as caterpillars during the dry season, which are unable to escape from the flames resulting in high impacts on local population (the species was not captured up to the end of this study). In addition, based on host plant species reported in the literature, we assigned a broader host plant range to M. helenor, suggesting that a generalist diet could help in the maintenance of individuals during the dry season, as they have more options to breed all year round. A better understanding of the temporal dynamics of adult and immature stages could help predict the amplitude of the impacts of dry season fire events on insects, especially when preventive fires are strategically used inside protected areas.
Massive pulmonary embolism in a COVID-19 patient: a case report
Authors: Sang Charlie J , Heindl Brittain , Von Mering Gregory , Rajapreyar Indranee
Published: October 2020

Background

Myocardial injury is associated with excess mortality in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections, and the mechanisms of injury are diverse. Coagulopathy associated with this infection may have unique cardiovascular implications.

Case summary

We present a case of 62-year-old male who presented after experiencing syncope and cardiac arrest. Given the clinical presentation and electrocardiographic findings, there was concern for acute coronary syndrome. However, coronary angiogram did not reveal significant coronary obstruction. Due to the unclear nature of his presentation, a bedside echocardiogram was rapidly performed and was indicative of right ventricular strain. Due to these findings, a pulmonary angiogram was performed that revealed massive pulmonary embolism. He successfully underwent catheter-directed thrombolysis and, after a prolonged hospital stay, was discharged home on lifelong anticoagulation.

Discussion

The impact of coronavirus disease-2019 (COVID-19) on the cardiovascular system has been prominent and multifaceted. COVID-19 can have wide-ranging effects on the cardiovascular system due to coagulopathy with resultant venous and arterial thrombo-embolism. Due to the critical condition of many patients affected by COVID-19, imaging for thrombo-embolic events is often delayed. With the use of bedside echocardiogram, observation of right ventricular strain may be critical in raising suspicion for pulmonary embolism, especially when atypical features are noted on electrocardiogram.
Management of refractory angina: an update
Authors: Davies Allan , Fox Kim , Galassi Alfredo R , Banai Shmuel , Ylä-Herttuala Seppo , Lüscher Thomas F
Published: October 2020

Despite the use of anti-anginal drugs and/or percutaneous coronary interventions (PCI) or coronary artery bypass grafting, the proportion of patients with coronary artery disease who have daily or weekly angina ranges from 2% to 24%. Refractory angina refers to long-lasting symptoms (for >3 months) due to established reversible ischaemia, which cannot be controlled by escalating medical therapy with the use of 2nd- and 3rd-line pharmacological agents, bypass grafting, or stenting. While there is uncertain prognostic benefit, the treatment of refractory angina is important to improve the quality of life of the patients affected. This review focuses on conventional pharmacological approaches to treating refractory angina, including guideline directed drug combination and dosages. The symptomatic and prognostic impact of advanced and novel revascularization strategies such as chronic total occlusion PCI, transmyocardial laser revascularization, coronary sinus occlusion, radiation therapy for recurrent restenosis, and spinal cord stimulation are also covered and recommendations of the 2019 ESC Guidelines on the Diagnosis and Management of Chronic Coronary Syndromes discussed. Finally, the potential clinical use of current angiogenetic and stem cell therapies in reducing ischaemia and/or pain is evaluated.
Clinical characterization of the first Belgian SCN5A founder mutation cohort
Authors: Sieliwonczyk Ewa , Alaerts Maaike , Robyns Tomas , Schepers Dorien , Claes Charlotte , Corveleyn Anniek , Willems Rik , Van Craenenbroeck Emeline M , Simons Eline , Nijak Aleksandra , Vandendriessche Bert , Mortier Geert , Vrints Christiaan , Koopman Pieter , Heidbuchel Hein , Van Laer Lut , Saenen Johan , Loeys Bart
Published: October 2020

Aims

We identified the first Belgian SCN5A founder mutation, c.4813 + 3_4813 + 6dupGGGT. To describe the clinical spectrum and disease severity associated with this mutation, clinical data of 101 SCN5A founder mutation carriers and 46 non-mutation carrying family members from 25 Belgian families were collected.

Methods and results

The SCN5A founder mutation was confirmed by haplotype analysis. The clinical history and electrocardiographic parameters of the mutation carriers and their family members were gathered and compared. A cardiac electrical abnormality was observed in the majority (82%) of the mutation carriers. Cardiac conduction defects, defined as PR or QRS prolongation on electrocardiogram (ECG), were most frequent, occurring in 65% of the mutation carriers. Brugada syndrome (BrS) was the second most prevalent phenotype identified in 52%, followed by atrial dysrythmia in 11%. Overall, 33% of tested mutation carriers had a normal sodium channel blocker test. Negative tests were more common in family members distantly related to the proband. Overall, 23% of the mutation carriers were symptomatic, with 8% displaying major adverse events. As many as 13% of the patients tested with a sodium blocker developed ventricular arrhythmia. One family member who did not carry the founder mutation was diagnosed with BrS.

Conclusion

The high prevalence of symptoms and sensitivity to sodium channel blockers in our founder population highlights the adverse effect of the founder mutation on cardiac conduction. The large phenotypical heterogeneity, variable penetrance, and even non-segregation suggest that other genetic (and environmental) factors modify the disease expression, severity, and outcome in these families.
Development and application of a real-time loop-mediated isothermal amplification method for quantification of Acetobacter aceti in red wine
Authors: Zhang Jingfeng , Wang Li , Shi Lei , Chen Xun , Liang Meidan , Zhao Lichao
Published: October 2020

This study reports the development and optimization of a real-time loop-mediated isothermal amplification (qLAMP) method for rapid detection of Acetobacter aceti strain in red wine samples. Our results showed that the primers and probes designed for 16S rRNA were effective for A. aceti detection. The quantification limit of real-time polymerase chain reaction (qPCR) and qLAMP in pure culture was 2.05 × 101 colony forming units (CFU) mL−1. qLAMP had a sensitivity of 6.88 × 101 CFU mL−1 in artificially contaminated Changyu dry red wine (CDRW) and Changyu red wine (CRW), and 6.88 × 102 CFU mL−1 in artificially contaminated Greatwall dry red wine (GDRW), which was 10 times higher than that of qPCR. In conclusion, this newly developed qLAMP is a reliable, rapid and accurate method for the detection and quantification of A. aceti species in red wine samples. Furthermore, our work provides a standard reference method for the quantitative detection of A. aceti and other acetic acid bacteria during the fermentation and storage of red wine samples.
Upper Respiratory Tract Levels of Severe Acute Respiratory Syndrome Coronavirus 2 RNA and Duration of Viral RNA Shedding Do Not Differ Between Patients With Mild and Severe/Critical Coronavirus Disease 2019
Authors: Yilmaz Aylin , Marklund Emelie , Andersson Maria , Nilsson Staffan , Andersson Lars-Magnus , Lindh Magnus , Gisslén Magnus
Published: October 2020

This study reports longitudinal viral RNA loads from the nasopharynx/throat in patients with mild and severe/critical coronavirus disease 2019 (COVID-19). We also investigated whether the duration of symptoms correlated with the duration of viral RNA shedding. A total of 56 patients were included. The highest viral loads occurred early after onset of symptoms. Neither the viral RNA loads in the upper respiratory tract nor the time to viral RNA clearance differed between patients with mild or severe/critical disease. There was a moderate correlation between number of days with symptoms and number of days with viral RNA shedding in patients with mild COVID-19.
Does the fossil fuel divestment movement impact new oil and gas fundraising?
Authors: Cojoianu Theodor F , Ascui Francisco , Clark Gordon L , Hoepner Andreas G F , Wójcik Dariusz
Published: October 2020

This article explores whether increasing fossil fuel divestment commitments are related to the reduction of capital flows into the oil and gas sector, based on an analysis of syndicated lending, equity and bond underwriting across 33 countries from 2000 to 2015. We find that increasing oil and gas divestment pledges in a country are associated with lower capital flows to domestic oil and gas companies. This effect is enhanced in more stringent environmental policy regimes and diminished in countries which heavily subsidise fossil fuels. However, the divestment movement may have an unintended effect, insofar as domestic banks situated in countries with high divestment commitments and stringent environmental policies provide more finance to oil and gas companies abroad. We explain these findings through the lens of institutional theory and show how both regulatory and socially normative elements of institutions shape this dynamic.
Effects of Quercetin on the Growth and Expression of Immune-Pathway-Related Genes in Silkworm (Lepidoptera: Bombycidae)
Authors: Shi Guiqin , Kang Zhaoyang , Ren Fei , Zhou Yuan , Guo Penglei
Published: October 2020

Quercetin is a flavonoid produced as a defense by plants. The effects of 1% quercetin on the growth and development of Bombyx mori were studied. The activities of the enzymes superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), carboxy-lesterase (CarEs), and glutathione S-transferase (GST) were all measured at 24, 48, 72, and 96 h after quercetin exposure. The results show that quercetin induces the activities of antioxidant and detoxification enzymes. With longer exposure times, enzyme activity first increased and then decreased. The relative expressions of AMP (defensin, CecA), the Toll pathway (cactus, Spatzle, and Rel), the IMD pathway (Imd, Fadd, and Dorsal), the JAK-STAT pathway (STAT, HOP, and Pi3k60), and the Melanization gene (DDC and PAH) were analyzed using quantitative polymerase chain reaction (qPCR). The results indicated that long-term exposure to quercetin could inhibit the expression of immune-related pathway genes in silkworms. This suggests that it can inhibit the activities of antioxidant and detoxifying enzymes, thus inhibiting the immune system and affecting the growth and development, resulting in an increase in the death rate in silkworm. This study provides the novel conclusion that quercetin accumulation inhibits the immune system of silkworm and increases its death rate, a result that may promote the development and utilization of better biopesticides that avoid environmental pollution.
Elucidation of enzymes involved in the biosynthetic pathway of bioactive polyacetylenes inBidens pilosausing integrated omics approaches
Authors: Chung Hisao-Hang , Ting Hieng-Ming , Wang Wei-Hsi , Chao Ya-Ting , Hsieh Cheng-Han , Apaya Maria Karmella , Sung Yi-Chang , Lin Shih-Shun , Hwu Fang-Yu , Shyur Lie-Fen
Published: October 2020

Polyacetylene compounds from Bidens pilosa are known to have several pharmacological activities. In this study, we identified major genes encoding enzymes involved in the biosynthesis of polyacetylene in B. pilosa. Seven polyacetylene metabolites present in B. pilosa leaves were induced by methyl jasmonate (MeJA) treatment and physical wounding. Transcriptome analysis via high-throughput sequencing revealed 39 202 annotated gene fragment sequences. A DNA microarray established by the 39 202 annotated genes was used to profile gene expression in B. pilosa leaf and root tissues. As no polyacetylene compounds were found in roots, the gene expression pattern in root tissue was used as a negative control. By subtracting MeJA-induced genes in roots, we obtained 1216 genes in leaves showing an approximate three-fold increase in expression post-MeJA treatment. Nine genes encoding enzymes with desaturation function were selected for confirmation of expression by qRT–PCR. Among them, two genes, BPTC030748 and BPTC012564, were predicted to encode Δ12-oleate desaturase (OD) and Δ12-fatty acid acetylenase (FAA), respectively. In B. pilosa leaves, RNAi knock-down concomitantly decreased, while virus-mediated transient overexpression of either gene elevated polyacetylene content. In summary, we demonstrate that two important enzymes, Δ12-oleate desaturase and Δ12-fatty acid acetylenase, involved in desaturation of linear fatty acid precursors play a role in polyacetylene biosynthesis in an important medicinal plant, Bidens pilosa.
CRISPR/Cas-mediated chromosome engineering: opening up a new avenue for plant breeding
Authors: Rönspies Michelle , Schindele Patrick , Puchta Holger
Published: October 2020

The advent of powerful site-specific nucleases, particularly the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (Cas) system, which enables precise genome manipulation, has revolutionized plant breeding. Until recently, the main focus of researchers has been to simply knock-in or knock-out single genes, or to induce single base changes, but constant improvements of this technology have enabled more ambitious applications that aim to improve plant productivity or other desirable traits. One long-standing aim has been the induction of targeted chromosomal rearrangements (crossovers, inversions, or translocations). The feasibility of this technique has the potential to transform plant breeding, because natural rearrangements, like inversions, for example, typically present obstacles to the breeding process. In this way, genetic linkages between traits could be altered to combine or separate favorable and deleterious genes, respectively. In this review, we discuss recent breakthroughs in the field of chromosome engineering in plants and their potential applications in the field of plant breeding. In the future, these approaches might be applicable in shaping plant chromosomes in a directed manner, based on plant breeding needs.
The nature of the symbiotic candidate 2MASS J07363415+6538548 in the field of NGC 2403
Authors: Merc J , Gális R , Kára J , Wolf M , Vrašťák M
Published: October 2020

New Online Database of Symbiotic Variables includes several poorly characterized objects and candidate symbiotic stars, not only in the Milky Way but also in other galaxies. The goal of the research presented in this paper was to reveal the nature of 2MASS J07363415+6538548, the object discovered as an X-ray source in the field of NGC 2403, and tentatively classified as a symbiotic candidate or a cataclysmic variable. By analysis of available photometric data from ground-based surveys, together with a high-precision photometry from TESS, remarkable astrometric measurements of the Gaia satellite and observations of other surveys spanning from X-rays to infrared, we have found that the object neither not a symbiotic star nor a cataclysmic variable, but rather an active K-type dwarf. The star is located in the distance of 415 pc, has an effective temperature of 4275 K, luminosity of 0.14 L⊙, mass of 0.7 M⊙, and radius of 0.7 R⊙. It has a rotational period ∼ 3 d and is a strong X-ray source with the X-ray luminosity of ∼ $10^{30}\rm \, erg\, s^{-1}$. Gyrochronology and isochrone fitting confirmed that the star is young.
RAiSERed: radio continuum redshifts for lobed active galactic nuclei
Authors: Turner Ross J , Drouart Guillaume , Seymour Nick , Shabala Stanislav S
Published: October 2020

Next-generation radio surveys are expected to detect tens of millions of active galactic nuclei (AGNs) with a median redshift of $z$ ≥ 1. Beyond targeted surveys, the vast majority of these objects will not have spectroscopic redshifts, while photometric redshifts for high-redshift AGNs are of limited quality, and even then require optical and infrared photometry. We propose a new approach to measure the redshifts of lobed radio galaxies based exclusively on radio-frequency imaging and broad-band radio photometry. Specifically, our algorithm uses the lobe flux density, angular size and width, and spectral shape to derive probability density functions for the most likely source redshift based on the Radio AGN in Semi-analytic Environments dynamical model. The full physically based model explains 70 per cent of the variation in the spectroscopic redshifts of a high-redshift (2 < $z$ < 4) sample of radio AGNs, compared to at most 27 per cent for any one of the observed attributes in isolation. We find that upper bounds on the angular size, as expected for unresolved sources, are sufficient to yield accurate redshift measurements at $z$ ≥ 2. The error in the model upon calibration using at least nine sources with known spectroscopic redshifts is <14 per cent in redshift (as 1 + $z$) across all redshifts. We provide the python code for the calculation and calibration of our radio continuum redshifts in an online library.
Braking indices of young radio pulsars: theoretical perspective
Authors: Igoshev Andrei P , Popov Sergei B
Published: October 2020

Recently, Parthsarathy et al. analysed long-term timing observations of 85 young radio pulsars. They found that 15 objects have absolute values of braking indices ranging ∼10–3000, far from the classical value n = 3. They also noted a mild correlation between measured value of n and characteristic age of a radio pulsar. In this article, we systematically analyse possible physical origin of large braking indices. We find that a small fraction of these measurements could be caused by gravitational acceleration from an unseen ultra-wide companion of a pulsar or by precession. Remaining braking indices cannot be explained neither by pulsar obliquity angle evolution, nor by complex high-order multipole structure of the poloidal magnetic field. The most plausible explanation is a decay of the poloidal dipole magnetic field which operates on a time-scale ∼104−105 yr in some young objects, but has significantly longer time-scale in other radio pulsars. This decay can explain both amplitude of measured n and some correlation between n and characteristic age. The decay can be caused by either enhanced crystal impurities in the crust of some isolated radio pulsars or, more likely, by enhanced resistivity related to electron scattering off phonons due to slow cooling of low-mass neutron stars. If this effect is indeed the main cause of the rapid magnetic field decay manifesting as large braking indices, we predict that pulsars with large braking indices are hotter in comparison to those with n ≈ 3.
The effect of cooling on the accretion of circumprimary discs in merging supermassive black hole binaries
Authors: Fontecilla Camilo , Lodato Giuseppe , Cuadra Jorge
Published: October 2020

At the final stages of a supermassive black hole coalescence, the emission of gravitational waves will efficiently remove energy, and angular momentum from the binary orbit, allowing the separation between the compact objects to shrink. In the scenario where a circumprimary disc is present, a squeezing phase will develop, in which the tidal interaction between the disc and the secondary black hole could push the gas inwards, enhancing the accretion rate on to the primary and producing what is known as an electromagnetic precursor. In this context, using 3D hydrodynamic simulations, we study how an adiabatic circumprimary accretion disc responds to the varying gravitational potential as the secondary falls on to the more massive object. We included a cooling prescription controlled by the parameter β = Ωtcool, which will determine how strong the final accretion rate is: a hotter disc is thicker, and the tidal interaction is suppressed for the gas outside the binary plane. Our main results are that for scenarios where the gas cannot cool fast enough (β ≥ 30), the disc becomes thick and renders the system invisible, while for β ≤ 10 the strong cooling blocks any leakage on to the secondary’s orbit, allowing an enhancement in the accretion rate of two orders of magnitude stronger than the average through the rest of the simulation.
Four-billion year stability of the Earth–Mars belt
Authors: Huang (黄宇坤) Yukun , Gladman Brett
Published: October 2020

Previous work has demonstrated orbital stability for 100 Myr of initially near-circular and coplanar small bodies in a region termed the ‘Earth–Mars belt’ from 1.08 < a < 1.28 au. Via numerical integration of 3000 particles, we studied orbits from 1.04–1.30 au for the age of the Solar system. We show that on this time-scale, except for a few locations where mean-motion resonances with Earth affect stability, only a narrower ‘Earth–Mars belt’ covering a ∼ (1.09, 1.17) au, e < 0.04, and I < 1° has over half of the initial orbits survive for 4.5 Gyr. In addition to mean-motion resonances, we are able to see how the ν3, ν4, and ν6 secular resonances contribute to long-term instability in the outer (1.17–1.30 au) region on Gyr time-scales. We show that all of the (rather small) near-Earth objects (NEOs) in or close to the Earth–Mars belt appear to be consistent with recently arrived transient objects by comparing to a NEO steady-state model. Given the <200 m scale of these NEOs, we estimated the Yarkovsky drift rates in semimajor axis and use these to estimate that a diameter of ∼100 km or larger would allow primordial asteroids in the Earth–Mars belt to likely survive. We conclude that only a few 100-km sized asteroids could have been present in the belt’s region at the end of the terrestrial planet formation.
Precise astrometry and diameters of asteroids from occultations – a data set of observations and their interpretation
Authors: Herald David , Gault David , Anderson Robert , Dunham David , Frappa Eric , Hayamizu Tsutomu , Kerr Steve , Miyashita Kazuhisa , Moore John , Pavlov Hristo , Preston Steve , Talbot John , Timerson Brad
Published: October 2020

Occultations of stars by asteroids have been observed since 1961, increasing from a very small number to now over 500 annually. We have created and regularly maintain a growing data set of more than 5000 observed asteroidal occultations. The data set includes the raw observations, astrometry at the 1 mas level based on centre of mass or figure (not illumination), where possible the asteroid’s diameter to 5 km or better, and fits to shape models, the separation and diameters of asteroidal satellites, and double star discoveries with typical separations being in the tens of mas or less. The data set is published at NASA’s Planetary Data System and is regularly updated. We provide here an overview of the data set, discuss the issues associated with determining the astrometry and diameters, and give examples of what can be derived from the data set. We also compare the occultation diameters of asteroids with the diameters measured by the satellites NEOWISE, AKARI AcuA, and IRAS, and show that the best satellite-determined diameter is a combination of the diameters from all three satellites.
PLncDB V2.0: a comprehensive encyclopedia of plant long noncoding RNAs
Authors: Jin Jingjing , Lu Peng , Xu Yalong , Li Zefeng , Yu Shizhou , Liu Jun , Wang Huan , Chua Nam-Hai , Cao Peijian
Published: October 2020

Long noncoding RNAs (lncRNAs) are transcripts longer than 200 nucleotides with little or no protein coding potential. The expanding list of lncRNAs and accumulating evidence of their functions in plants have necessitated the creation of a comprehensive database for lncRNA research. However, currently available plant lncRNA databases have some deficiencies, including the lack of lncRNA data from some model plants, uneven annotation standards, a lack of visualization for expression patterns, and the absence of epigenetic information. To overcome these problems, we upgraded our Plant Long noncoding RNA Database (PLncDB, http://plncdb.tobaccodb.org/), which was based on a uniform annotation pipeline. PLncDB V2.0 currently contains 1 246 372 lncRNAs for 80 plant species based on 13 834 RNA-Seq datasets, integrating lncRNA information from four other resources including EVLncRNAs, RNAcentral and etc. Expression patterns and epigenetic signals can be visualized using multiple tools (JBrowse, eFP Browser and EPexplorer). Targets and regulatory networks for lncRNAs are also provided for function exploration. In addition, PLncDB V2.0 is hierarchical and user-friendly and has five built-in search engines. We believe PLncDB V2.0 is useful for the plant lncRNA community and data mining studies and provides a comprehensive resource for data-driven lncRNA research in plants.
A new experimental phenomenological method to explore the subjective features of psychological phenomena: its application to binocular rivalry
Authors: Niikawa Takuya , Miyahara Katsunori , Hamada Hiro Taiyo , Nishida Satoshi
Published: October 2020

The subjective features of psychological phenomena have been studied intensively in experimental science in recent years. Although various methods have been proposed to identify subjective features of psychological phenomena, there are elusive subjective features such as the spatiotemporal structure of experience, which are difficult to capture without some additional methodological tools. We propose a new experimental method to address this challenge, which we call the contrast-based experimental phenomenological method (CEP). CEP proceeds in four steps: (i) front-loading phenomenology, (ii) online second-personal interview, (iii) questionnaire survey, and (iv) hypotheses testing. It differs from other experimental phenomenological methods in that it takes advantage of phenomenal contrasts in collecting phenomenological data. In this paper, we verify the validity and productivity of this method by applying it to binocular rivalry (BR). The study contributes to empirical research on BR in three respects. First, it provides additional evidence for existing propositions about the subjective features of BR: e.g. the proposition that the temporal dynamics of the experience depend upon subject-dependent parameters such as attentional change. Second, it deepens our understanding of the spatiotemporal structures of the transition phase of BR. Third, it elicits new research questions about depth experience and individual differences in BR. The presence of such contributions demonstrates the validity and productivity of CEP.
Safety of Outpatient Parenteral Antimicrobial Therapy in Nonagenarians
Authors: Shrestha Nabin K , Blaskewicz Caitlin , Gordon Steven M , Everett Angela , Rehm Susan J
Published: October 2020

Background

Although widely accepted for adults, the safety of outpatient parenteral antimicrobial therapy (OPAT) in very old patients has not been examined.

Methods

Nonagenarians (age ≥90 years) discharged from the hospital on OPAT over a 5-year period were identified from the Cleveland Clinic OPAT Registry. Three matched controls (<90 years) were selected for each nonagenarian. Times to OPAT-related emergency department (ED) visit and OPAT-related readmission were compared across the 2 groups in multivariable subdistribution proportional hazards competing risks regression models. Incidence of adverse drug events and vascular access complications were compared using negative binomial regression.

Results

Of 126 nonagenarians and 378 controls, 7 were excluded for various reasons. Among the remaining 497 subjects, 306 (62%) were male, 311 (63%) were treated for cardiovascular or osteoarticular infections, and 363 (73%) were discharged to a residential health care facility. The mean (SD) ages of nonagenarians and controls were 92 (2) and 62 (16) years, respectively. Compared with matched controls, being a nonagenarian was not associated with increased risk of OPAT-related ED visit (hazard ratio [HR], 0.77; 95% CI, 0.33–1.80; P = .55), OPAT-related readmission (HR, 0.78; 95% CI, 0.28–2.16; P = .63), adverse drug event from OPAT medications (incidence rate ratio [IRR], 1.00; 95% CI, 0.43–2.17; P = .99), or vascular access complications (IRR, 0.66; 95% CI, 0.27–1.51; P = .32). Nonagenarians had a higher risk of death overall (HR, 2.64; 95% CI, 1.52–4.58; P < .001), but deaths were not from OPAT complications.

Conclusions

Compared with younger patients, OPAT in nonagenarians is not associated with higher risk of OPAT-related complications. OPAT can be provided as safely to nonagenarians as to younger patients.