bluuebunny/crossref_metadata_2025 huggingface dataset:
Beneficiated ponded fly ash for concretes with high volume mineral additions
Authors: Zaichenko Nikolai , Petrik Irina , Zaichenko Liudmila
Published: July 2020

The article presents the investigation results of effect of beneficiated ponded fly ash on the properties of cement pastes and concretes with high-level replacement of Portland cement. To improve the characteristics of ponded fly ash meeting technical requirements for replacing cement in concrete the triboelectrostatic beneficiation technology has been elaborated. This technology can produce low-carbon ash product (LOI = 2.52 % in this study) for the high replacing level of cement (45 %) in concretes. The beneficiated ponded fly ash has an improved granulometric and phase composition, a decreased content of unburned carbon that accelerates the hydration process of cement, increases the rheological properties of cement paste and the ability of air-entraining admixture to hold the required involved air. In a combination with the nanostructured-carbon-based plasticizing admixture the beneficiated ponded fly ash exhibits high rate of strength increase when is used in high-volume fly ash concretes.
On the possibility of using lime dust for the production of building materials of forced carbonate hardening
Authors: Bakhtin Aleksandr , Lyubomirskiy Nikolai , Fedorkin Sergey , Bakhtina Tamara
Published: July 2020

The paper presents research on the development of building materials with low level of CO2emissions based on technogenic recycled materials. The paper addresses the determination of optimal formulation and technological parameters of obtaining materials based on lime dust generated by mechanical deposition in cyclones and bag filters of shaft furnaces, as well as finely dispersed marble limestone with a fraction of up to 5 mm. Studies have shown that it is possible to obtain carbonized material with compressive strength of more than 40 MPa from this recycled material by forced carbonization used during three hours. Moreover, to obtain such numbers, the optimal content of lime dust in raw materials should be in the range of 35-40% wt. when the water content of the mixture is 6-7% wt. The carbonized material obtained with the indicated technological parameters will have an average density of 1.95-2.0 g/cm3 and water absorption by weight of not more than 12%.
Influence of pH liquid for mixing gypsum binders on the strength of gypsum composites
Authors: Petropavlovskaya Victoria , Zavadko Maria , Novichenkova Tatiana
Published: July 2020

The influence of fluid acidity on the processes of hardness, mechanism, kinetics, properties of gypsum stone are of great interest.Studies of these processes for modified composites based on gypsum and heavy high density and basalt additives can improve the modifier's effectiveness. The influence of the pH of a liquid on the processes of structure formation and the properties of composites is determined in this work. It is shown that the pH should be shared by other structure-forming factors. This is the chemical composition of basalt waste, its percentage, the interaction of its oxides with pore fluid and natural minerals are the products of their reaction. The regulation of the material composition of composites can enhance the properties and also lead to degradation of structures.
Residual life assessment of welded joints in the girth weld root
Authors: Shron Leonid , Bogutsky Vladimir , Yagyaev Elmar , Tabolin Illa
Published: July 2020

The article analyzes the influence of the structural crack-like defect in the girth weld root welding the bottom to the collector body on the crack growth resistance. A mathematical model has been developed to estimate the residual life resource of welded joints with an internal crack-like defect in the root of the weld under creep. Results of metallographic studies of bench tests results for the welded joints long-term strength formed the basis of the calculation model. In all tested models the cracks start at the top of the narrow structural gap in the weld root and develop along almost the entire weld axis, perpendicular to the wall of the pipe and have a discrete growth pattern. As a result, discrete rupture of material occurs on a length of rc, and the initial crack is incremented by this length. After that, a “plastic core” of rc length is formed in the newly formed crack tip, additional damage is accumulated, and the crack development process continues until the stress level in the section weakened by the crack reaches a critical value. The obtained dependence characterizes the crack growth time from the initial crack-like defect to its critical length.
The study of the regularities of structure formation and properties of the L-PBF metal as a set of processes on the way to create a controlled structure
Authors: Shakirov Ivan , Kuznetsov Pavel , Staritsyn Mikhail , Zhukov Anton , Bobyr Vitaliy
Published: July 2020

In this work, to study the effect of laser powder bed fusion (L-PBF) parameters on the microstructure and mechanical properties of 321 austenitic steel, a series of samples were created combining various combinations of L-PBF technological modes, such as: laser spot diameter, scanning speed, laser power, scanning strategy. The possibility of controlling the structure formation of steel in the L-PBF process with the aim of obtaining a given crystallographic texture, grain size and morphology is estimated. The relationship between the resulting anisotropic structure and mechanical properties is investigated.
Analysis and optimization of rubidium spectrum lamp to eliminate frequency fluctuations of rubidium atomic frequency standard
Authors: Lian Jiqing , Zhang Jinhai , Shi Fucheng , Zhang Jun , Wei Lixun , Wang Kuan
Published: July 2020

Rubidium atomic frequency standard (RAFS) is the most widely used frequency standard in space. The light used to pump the atoms and detect the resonance signal is emitted by rubidium spectrum lamp, so the light intensity of rubidium spectrum lamp directly determines the performance of RAFS. This paper discussed on-board RAFS’ output frequency fluctuations caused by rubidium spectrum lamp. The reason of frequency fluctuations from rubidium lamps was described. To obtain stable lamp light intensity, analysis and optimization of the lamp was developed. Relevant experiments were carried out to verify the optimization. The study content of this paper is beneficial to improve the performance of a single temperature controlled space RAFS physics package.
Simulation and Experimental Research on a Gas Liquid Separator with Rotary Impeller
Authors: Wang Baihui , Li Yingbin , Deng Mingjun , Shi Baolu , Shang Wenjin , Xu Bo
Published: July 2020

Gas-liquid separation technology under microgravity is the basis for various gas and liquid treatments on a manned spacecraft, which has a wide range of applications in Environmental Control and Life Support System. Dynamic gas-liquid separator is commonly used for the separation of gas-liquid two-phase flow, which has two essential performance parameters called liquid outlet pressure and separating efficiency. Predicting these two parameters accurately under a specific structure has guiding significance for design and application of the dynamic gas-liquid separator. In this study, CFD simulations were conducted using the Volume of Fluid (VOF) model at steady state conditions. In addition, experiments were designed to verify the accuracy of numerical results. Finally, the performance of the separator under microgravity was predicted. It is showed that the simulation method can be utilized to determine the transport performance of dynamic gas-liquid separator, which has significant value in design and optimization.
Research on the Application of Carbon Foam Absorbing Materials in Wireless Testing of Spacecraft Thermal Vacuum Test
Authors: Chun-lin Du , Xiao-fang Yin , Jia-yong Qin , Xiao-ning Liu , Yu-wei Sun , Yao Feng
Published: July 2020

With the rise of mobile communication satellites and low-orbit Internet satellite constellations, wireless testing is required in spacecraft thermal vacuum test, and a comprehensive thermal testing environment for vacuum low-temperature absorption is needed. This paper clarifies the key parameters that need to be paid attention to in the application of vacuum absorbing materials under vacuum and low temperature environment, gives reference indexes, and puts forward the technical process and test results for the development of absorbing shroud.
Antioxidant activity of citron peel (Citrus medica L.) essential oil and extract on stabilization of sunflower oil
Authors: Okhli Somayeh , Mirzaei Habibollah , Hosseini Seyed Ebrahim
Published: July 2020

Due to the unfavorable effects of synthetic antioxidants, the use of various sources of plant antioxidants to prevent foods oxidation, especially oil-based or fat-based varieties, has been recently got considerable attention. In this study, the antioxidant effect of essential oil and extract from the citron fruit (Citrus medica L.) was investigated on the thermal stability of sunflower oil. Aqueous, ethanolic, and methanolic extracts of citron peel (800 ppm), BHT synthetic antioxidant (200 ppm), and citron peel essential oil (800 ppm) were added to sunflower oil. The oil oxidation stability was evaluated during 5 days through analyzing the values of peroxide, anisidine, thiobarbituric acid, totox, and oxidative stability index (OSI). Results showed that the peroxide, anisidine, and totox value had an increasing trend over time. The effects of storage time, extract, and essential oil were statistically significant in reducing the oxidation rate of sunflower oil during storage. Ultrasonic-assisted ethanolic extract at 30 min showed the highest OSI. The results of this study demonstrated the positive effects of citron peel extract essential oil and on sunflower oil stability and its superiority over synthetic antioxidants.
Zusammenfassende Darstellung der wissenschaftlichen Grundlagen der
Richtlinie der Bundesärztekammer zur Durchführung der
substitutionsgestützten Behandlung
Opioidabhängiger
Authors: Kunstmann Wilfried , Specka Michael , Wodarz Norbert , Scherbaum Norbert
Published: July 2020

Hintergrund Mit § 5 Abs. 12 BtMVV wurde die
Bundesärztekammer beauftragt, in einer Richtlinie den allgemein
anerkannten Stand der Erkenntnisse der medizinischen Wissenschaft zur
Substitutionsbehandlung Opioidabhängiger festzustellen.

Methode Für die initiale Fassung der Richtlinie der
Bundesärztekammer (BÄK) von 2002 war eine umfangreiche
wissenschaftliche Literaturrecherche durchgeführt und deren
Ergebnisse nach Evidenzklassen kategorisiert worden. Für die
nachfolgenden Überarbeitungen 2010 und 2017 wurden neuere
systematische Übersichtsarbeiten und Studien der Evidenzklassen
I–III ergänzt und mit internationalen Leitlinien zur
Substitutionsbehandlung abgeglichen.

Ergebnisse Mit einer Substitutionsbehandlung können
verschiedene gesundheitliche, suchtbezogene sowie psychische und soziale
Ziele verfolgt werden. Die Mortalitätsrate wird durch die Behandlung
reduziert, und bei 70 bis 80 % der Behandelten lässt sich
durch die Substitution der meist hochriskante Konsum illegal erworbener
Opioide weitgehend eindämmen. Durch eine psychosoziale Begleitung
kann der Behandlungserfolg verbessert werden, weshalb sie regelhaft
empfohlen werden soll. Für die Frage, wann bei welchen Patienten
für welchen Zeitraum eine Take-home-Verordnung gerechtfertigt ist,
fehlt es an wissenschaftlichen Erkenntnissen.

Schlussfolgerungen Die Richtlinie der Bundesärztekammer wurde
mit ihrer Novellierung 2017 auf der Grundlage des aktuellen Standes der
Wissenschaft zur Substitutionsbehandlung überarbeitet. Damit wird
für die behandelnden Ärztinnen und Ärzte mehr
Rechtssicherheit geschaffen, und die Behandlung kann an dem bestehenden
wissenschaftlichen Erkenntnisstand ausgerichtet werden. Es muss nun
evaluiert werden, ob dies auch positive Auswirkungen auf die
Versorgungssituation Opioidabhängiger hat und mehr Ärztinnen
und Ärzte sich an der Versorgung beteiligen.
Die Bedeutung qualitativ hochwertiger Entlassbriefe: Eine empirische
Untersuchung
Authors: Piepenhagen Gerlinde , Röhrig Bernd , Eirund Wolfgang , Roth-Sackenheim Christa , Steffens Markus
Published: July 2020

Einleitung Der Entlassbrief ist Teil des Entlassmanagements. Er
informiert nachfolgend Behandelnde sowie Institutionen und unterstützt
die nahtlose Weiterbehandlung der Patienten. Vorliegende Studie untersucht
empirisch die Qualität von Entlassbriefen nach dem Aufenthalt in einer
psychiatrischen/psychosomatischen Klinik anhand einer selbst
entwickelten Kodierliste. Vorschläge zur Erstellung und Strukturierung
qualitativ hochwertiger Entlassbriefe werden gemacht.

Methode Bewertet wurden 50 Entlassbriefe anhand verschiedener Aspekte aus
der sozialpsychiatrischen bzw. sozialmedizinischen Begutachtung von jeweils 2
Ratern; bei Unstimmigkeiten in der Bewertung beider Rater wurde im Konsens
entschieden.

Ergebnisse Die Zeit von der Entlassung aus dem Krankenhaus bis zur
Fertigstellung des Entlassbriefs betrug im Mittel 22,4 Tage (Median: 15,0 Tage).
In 18% der Fälle lag der Entlassbrief zum Entlassungszeitpunkt
vor und in 14% innerhalb einer Woche. In 24% lag der
Entlassbrief erst nach 28 Tagen und länger vor. Die Medikation war in
97,5% der Fälle vollständig aufgeführt, zur
medizinischen Weiterbehandlung beim Facharzt fehlten jedoch in 50% die
Angaben. Bei der Empfehlung einer Weiterbehandlung (N=10, bspw.
Tagesklinik oder PIA), wurde diese lediglich in 3 Fällen eingeleitet. 28
Patienten hatten zum Aufnahmezeitpunkt ein Arbeitsverhältnis, bei 11
Personen fehlten die Angaben. Angaben zur Arbeitsfähigkeit zum
Aufnahmezeitpunkt waren in 44% vollständig und in 20%
unvollständig. Zum Entlassungszeitpunkt waren 7 Patienten
arbeitsfähig, 19 arbeitsunfähig und in 24 Entlassbriefen fehlte
die Angabe.

Schlussfolgerung Ein qualitativ hochwertiger Entlassbrief enthält
klare Formulierungen, ist strukturiert aufgebaut, enthält
ausschließlich relevante Informationen sowie ein eigenes Kapitel
„Therapieempfehlungen/Empfehlungen für das weitere
Vorgehen“. Elektronische Entlassbriefe mit automatisierter Einbeziehung
von Untersuchungsbefunden/Assessments sparen Zeit und Kosten bei der
Erstellung und beim Lesen.
Micro-osteoperforations and Its Effect on the Rate of Tooth Movement: A Systematic Review
Authors: Al-Khalifa Khalifa S. , Baeshen Hosam A.
Published: July 2020

Prolonged orthodontic treatments have inconvenienced patients and clinicians alike. Surgically assisted techniques for accelerating orthodontic tooth movement have shown promising results in the literature over the years. The minimally invasive nature of micro-osteoperforations (MOPs), however, for enhanced orthodontic tooth movement has recently gained momentum, with many clinical trials conducted on both animals and humans. An electronic search was performed to extract papers using PubMed, Google Scholar, Scopus, and Web of Science. The keywords that were used included “MOP,” “accelerating tooth movement,” “orthodontic tooth movement,” and “regional acceleratory phenomenon.” The studies that met our inclusion criteria were extracted and evaluated in this review. MOPs have been proven time and again, in animal and human studies alike, to increase the rate of orthodontic tooth movement. The application of perforations to cortical bone present in the pathway of teeth, which are specifically to be moved creates transient osteopenia. This reduces the density of the cortical bone, hence speeding up the rate of orthodontic tooth movement. Many techniques have been implemented and perfected to enhance orthodontic tooth movement and shorten the treatment time in the literature. MOPs have proven to be a universally applied, nontechnical, repeatable, and minimally invasive method of accelerating tooth movement, with extremely minimal consequences.
Realization of p-type ZnAgO:N thin films on flexible polyimide substrates through co-sputtering for wearable thermoelectric applications
Authors: Jeon Buil , Yoon Chongsei , Yoon Giwan
Published: July 2020

In this study, we deposited a series of Ag and N co-doped ZnO thin films (ZnAgO:N) with different Ag atomic percentage (at. %) ratios on flexible polyimide (PI) substrates to realize p-type ZnO-based thin films for wearable thermoelectric applications by in situ co-sputtering of ZnO and Ag by RF and DC magnetron sputtering in a mixture of Ar and N2O gases. To evaluate the thermoelectric performance of these ZnAgO:N thin films, we measured the Seebeck coefficient S and electrical conductivity σ of the thin films with various Ag at. % ratios and calculated the power factor S2σ. These measurements confirmed that the co-doping of Ag and N into ZnO is an effective method for fabricating p-type ZnAgO:N thin films with σ in the range of about 105–3.3 × 106 S/m, as a function of Ag at. % ratio on the flexible PI substrates. In addition, the presence of an optimal Ag at. % ratio that leads to a maximum S2σ for the p-type ZnAgO:N thin films was observed. Raman spectroscopy and x-ray photoelectron spectroscopy revealed that the p-type conductivity in ZnAgO:N thin films originates from the acceptors AgZn and NO formed by the co-dopants Ag and N. As a result, the S and σ of the p-type ZnAgO:N thin films were investigated to be affected significantly by the acceptors and defects formed by the Ag and N co-dopants in the thin films. The influence of AgZn and NO on the appearance of the p-type conductivity in ZnAgO:N thin films and S and σ of the thin films was intensively studied.
The thin film bulk acoustic wave resonator based on single-crystalline 43○Y-cut lithium niobate thin films
Authors: Bai Xiaoyuan , Shuai Yao , Lv Lu , Xing Ying , Zhao Jiaoling , Luo Wenbo , Wu Chuangui , Yang Tao , Zhang Wanli
Published: July 2020

43°Y-cut lithium niobate (LiNbO3, LN) single-crystalline thin films, which are integrated with two types of Bragg reflectors of W/SiO2 and Mo/SiO2, respectively, are fabricated by means of the crystal-ion-slicing technique. Crack-free LN thin films are obtained when the Mo/SiO2 reflector is adopted, while crumples take place when the LN thin film is combined with W/SiO2. Moreover, solidly-mounted-type thin film bulk acoustic wave resonators (LN-SMRs) based on the single-crystalline LN film and Bragg reflector layers of Mo/SiO2 are prepared and characterized. The results indicate that the LN thin film combined with the Mo/SiO2 reflector has good thin film quality, and keff2 of the LN-SMR reaches 20%.
Wind load prediction on single tree with integrated approach of L-system fractal model, wind tunnel, and tree aerodynamic simulation
Authors: Poh Hee Joo , Chan Woei Leong , Wise Daniel J. , Lim Chi Wan , Khoo Boo Cheong , Gobeawan Like , Ge Zhengwei , Eng Yong , Peng Jia Xin , Raghavan Venugopalan S. G. , Jadhav Siddharth Sunil , Lou Jing , Cui Y. D. , Lee Heow Pueh , Burcham Daniel Christopher , Lee Daryl , Li Kelvin Wenhui , Lee Irene
Published: July 2020

In this work, we adopt the integration of the L-system fractal tree generation, 3D printed wind tunnel modeling, and computational fluid dynamics (CFD) simulation approach to model the wind effect on a single tree. We compare the agreement between CFD simulations and wind tunnel measurements of rigid branched structures resembling trees. First, fractal tree mesh models based on species growth and branching patterns are developed to represent tree species for wind–tree modeling. Subsequently, a scaled-down fractal tree is generated with 3D-printing and subjected to tunnel testing with load cell and particle image velocimetry measurement data under the wind speed of 10 m/s and 15 m/s. Finally, CFD based on Reynolds-Average Navier–Stokes (RANS) simulation with a full closure model and Large Eddy Simulation (LES) using appropriate momentum sink and turbulence source terms for the volumetric tree is carried out. We use both the volume-average porous media and the volume-splitting discretized zones (split number 10 × 10 × 10) to reproduce the momentum sink effect in the numerical simulation. Three tree species, namely, Peltophorum pterocarpum (yellow flame), Khaya senegalensis (African mahogany), and Hopea odorata (ironwood), are tested, and a reasonable agreement of drag force prediction and velocity profiles is obtained when comparing the CFD simulation results with wind tunnel data. The RANS modeled drag force results exhibit 20% of over-prediction, while the normalized velocity profiles display a good match of velocity decay at the tree leeward sides. On the other hand, LES produces much better results with only 3% discrepancy with the experimental results. A comparison of experimental results among the tree species is also carried out. Due to the actual random wind direction, tree slenderness representation, and structural flexibility issues, the current methodology still has the limitation for validation with urban on-site measurement. Nonetheless, this integrated approach is the first step in establishing modeling tool applicability to examine the effect of the forest structure and composition on wind loads.
Improved methodology expands a line-by-line dataset of H216O
Authors: Patrick Chris
Published: July 2020

Data enhancement and network-theoretical validation techniques were used to revise a widely utilized 2013 dataset of the rovibrational transitions and empirical energy levels of H 2 16 O.
Fluctuations of the wall shear stress vector in a large-scale natural convection cell
Authors: du Puits R. , Bruecker C.
Published: July 2020

We report first experimental data of the wall shear stress in turbulent air flow in a large-scale Rayleigh–Bénard experiment. Using a novel, nature-inspired measurement concept [C. H. Bruecker and V. Mikulich, PLoS One 12, e0179253 (2017)], we measured the mean and fluctuating part of the two components of the wall shear stress vector at the heated bottom plate at a Rayleigh number Ra = 1.58 × 1010 and a Prandtl number Pr = 0.7. The total sampling period of 1.5 h allowed us to capture the dynamics of the magnitude and the orientation of the vector over several orders of characteristic timescales of the large-scale circulation. We found the amplitude of short-term (turbulent) fluctuations to be following a highly skewed Weibull distribution, while the long-term fluctuations are dominated by the modulation effect of a quasi-regular angular precession of the outer flow around a constant mean, the timescale of which is coupled to the characteristic eddy turnover time of the global recirculation roll. Events of instantaneous negative streamwise wall shear occur when rapid twisting of the local flow happens. A mechanical model is used to explain the precession by tilting the spin moment of the large circulation roll and conservation of angular momentum. A slow angular drift of the mean orientation is observed in a phase of considerable weakening of mean wind magnitude.
Analysis of properties of thermally deformed protein structure by using two different types of artificial intelligence
Authors: Nishiyama Katsuhiko
Published: July 2020

The thermal deformation of flexible protein structures affects the protein characteristics. However, the overall effects of deformation have not been fully investigated. In this study, the behaviors of tetrapeptides in active areas of a thermally deformed papain structure were analyzed by using a deep neural network, genetic programming, and computer simulations. Fifteen tetrapeptides were found to be compatible with the thermally deformed structure, and over half of them were incompatible with the structure without thermal deformation. A decision tree was used to show the attributes that governed the suitability of tetrapeptides in active areas.
The effect of dark matter on the Jeans instability with the q-nonextensive velocity distribution
Authors: Yang Weiheng , Chen Hui , Liu Sanqiu
Published: July 2020

Based on the framework of nonextensive statistics and its related kinetic theory, the Jeans instability in a self-gravitational system composed of dark and bright matters is restudied. The results show that the nonextensivity, the presence of dark matter, has significant effects on the dynamics of Jeans modes. With the increase in the q parameter and the ratio of dispersion velocities, as well as the decreased ratio of densities of dark to bright matters, both critical wave-numbers and growth rates of the instabilities are increased. In addition, as expected, when q → 1, the corresponding results for Maxwellian velocity distribution are recovered. The present results may shed new light on the comprehension of the intrinsic physical mechanism responsible for the collapse of interstellar gas clouds.
Defect, transport, and dopant properties of andradite garnet Ca3Fe2Si3O12
Authors: Kuganathan Navaratnarajah , Ganeshalingam Sashikesh , Chroneos Alexander
Published: July 2020

There is growing interest to discover suitable calcium containing oxides that can be used as electrode materials in calcium ion batteries. A comprehensive computational investigation of ionic defects and Ca-ion diffusion in Ca-bearing oxide materials at the atomic level is important so as to predict their suitability for use in Ca-ion batteries. In this study, we apply atomistic simulation techniques to examine the energetics of defects, dopants, and Ca-ion diffusion in Ca3Fe2Si3O12. The calculations suggest that the Ca/Fe anti-site defect is the most favorable intrinsic defect causing such significant disorder, which would be sensitive to synthesis conditions. Diffusion of Ca2+ ions within Ca3Fe2Si3O12 is three-dimensional, with the activation energy of migration of 2.63 eV inferring slow ionic conductivity. The most favorable isovalent defects are Mn2+, Sc3+, and Ge4+ on Ca, Fe, and Si, respectively, for this process. The formation of extra calcium was considered to increase the capacity and diffusion of Ca in this material. It is found that Al3+ and Mn2+ are the candidate dopants on the Si and Fe sites, respectively, for this process and there is a reduction observed in the activation energies. The electronic structures of favorable dopant configurations are discussed using density functional theory simulations.
Correlation between density and temperature fluctuations of hypersonic turbulent boundary layers at Ma∞ = 8
Authors: Li Xin , Tong Fu-Lin , Yu Chang-Ping , Li Xin-Liang
Published: July 2020

The correlation between density and temperature fluctuations (ρ′ and T′) of the turbulent boundary layer is significantly affected by wall temperature. Direct numerical simulation databases with the ratio of wall-to-recovery temperature Tw/Tr = 0.8 and 0.15 are considered. A fitting slope method and a two-dimensional correlation method are adopted to visualize the correlated behavior. The results show that an adverse trend and a separated correlated structure are found in the buffer region, which can be treated as the effects of the correlation of ρ′ and T′. To reveal the correlation, several statistical analyses are conducted. It indicates that the extreme events in the flow are suppressed with wall cooling; meanwhile, the small-scale fluctuations are enhanced. The behavior of the fluctuations results from the reduced mean swirling strength and the increased radius of the vortical structures.
Transcriptome analysis provides insights into the molecular bases in response to different nitrogen forms-induced oxidative stress in tea plant roots (Camellia sinensis)
Authors: Chen Ziping , Li Huiping , Yang Tianyuan , Chen Tingting , Dong Chunxia , Gu Quan , Cheng Xunmin
Published: July 2020

Previous studies have suggested that the maintenance of redox homeostasis is essential for plant growth. Here we investigated how redox homeostasis and signalling is modulated in response to different nitrogen (N) forms in tea plant roots. Our results showed that both N deficiency and nitrate (NO3–) can trigger the production of hydrogen peroxide and lipid peroxidation in roots. In contrast, these responses were not altered by NH4+. Further, N deficiency and NO3–-triggered redox imbalance was re-established by increased of proanthocyanidins (PAs) and glutathione (GSH), as well as upregulation of representative antioxidant enzyme activities and genes. To further explore the molecular bases of these responses, comparative transcriptome analysis was performed, and redox homeostasis-associated differentially expressed genes (DEGs) were selected for bioinformatics analysis. Most of these genes were involved in the flavonoid biosynthesis, GSH metabolism and the antioxidant system, which was specifically altered by N deficiency or NO3–. Moreover, the interplay between H2O2 (generated by RBOH and Ndufab1) and hormones (including abscisic acid, auxin, cytokinin and ethylene) in response to different N forms was suggested. Collectively, the above findings contribute to an understanding of the underlying molecular mechanisms of redox homeostasis and signalling in alleviating oxidative stress in tea plant roots.
Stem cell lineage survival as a noisy competition for niche access
Authors: Corominas-Murtra Bernat , Scheele Colinda L. G. J. , Kishi Kasumi , Ellenbroek Saskia I. J. , Simons Benjamin D. , van Rheenen Jacco , Hannezo Edouard
Published: July 2020

Significance

What defines the number and dynamics of the stem cells that generate and renew biological tissues? Although several molecular markers have been described to predict stem cell potential, we propose a complementary approach that mathematically describes “stemness” as an emergent property arising from a stochastic competition for space. We predict from that competition the robust emergence of a region made of functional stem cells, as well as give simple predictions on lineage-survival probability. We test our results with data obtained from intravital live-imaging experiments in mammary gland development, existing data from kidney development, and from the self-renewal of the crypt to show that our framework can predict the number of functional stem cells and lineage-survival probability.
Intercepting second-messenger signaling by rationally designed peptides sequestering c-di-GMP
Authors: Hee Chee-Seng , Habazettl Judith , Schmutz Christoph , Schirmer Tilman , Jenal Urs , Grzesiek Stephan
Published: July 2020

Significance

Cyclic diguanylate (c-di-GMP) regulates a wide range of bacterial cellular functions from biofilm formation to growth and survival. Based on the structural analysis of the complex of c-di-GMP with a bacterial effector protein followed by amino acid sequence optimization, we have developed a short peptide that binds c-di-GMP with nanomolar affinity and high specificity. This provides many opportunities for biotechnological and biomedical applications. In particular, we show that such an endogenously expressed peptide effectively reduces intracellular c-di-GMP and thereby inhibits and even disintegrates biofilms in
Pseudomonas aeruginosa
.
Bioinspired nervous signal transmission system based on two-dimensional laminar nanofluidics: From electronics to ionics
Authors: Teng Yunfei , Liu Pei , Fu Lin , Kong Xiang-Yu , Jiang Lei , Wen Liping
Published: July 2020

Significance

Mammalian nervous systems, as natural ionic circuitries, have interested researchers with their powerful abilities in environmental perceptions and information transmission, which triggered booming development in artificial prototypes such as biomimetic ionic nanochannels. Most studied artificial ionic systems are more focused on their functions of perception, whereas the ionic information transmission system is rarely reported. Here, two-dimensional laminar nanofluidics are fabricated from MXene nanosheets and the noncontact external electrostatic potential applied patterns to generate and transmit alternating signals, from basic sine to frequency-modulated binary information. This work demonstrates the potentiality of bioinspired nervous signal transmission to simulate the neural ion-carried information system, which might lead to the avenue of alternating current ionics.
Tyramide signal amplification mass spectrometry (TSA-MS) ratio identifies nuclear speckle proteins
Authors: Dopie Joseph , Sweredoski Michael J. , Moradian Annie , Belmont Andrew S.
Published: July 2020

We present a simple ratio method to infer protein composition within cellular structures using proximity labeling approaches but compensating for the diffusion of free radicals. We used tyramide signal amplification (TSA) and label-free mass spectrometry (MS) to compare proteins in nuclear speckles versus centromeres. Our “TSA-MS ratio” approach successfully identified known nuclear speckle proteins. For example, 96% and 67% of proteins in the top 30 and 100 sorted proteins, respectively, are known nuclear speckle proteins, including proteins that we validated here as enriched in nuclear speckles. We show that MFAP1, among the top 20 in our list, forms droplets under certain circumstances and that MFAP1 expression levels modulate the size, stability, and dynamics of nuclear speckles. Localization of MFAP1 and its binding partner, PRPF38A, in droplet-like nuclear bodies precedes formation of nuclear speckles during telophase. Our results update older proteomic studies of nuclear speckles and should provide a useful reference dataset to guide future experimental dissection of nuclear speckle structure and function.
TinGa: fast and flexible trajectory inference with Growing Neural Gas
Authors: Todorov Helena , Cannoodt Robrecht , Saelens Wouter , Saeys Yvan
Published: July 2020

Motivation

During the last decade, trajectory inference (TI) methods have emerged as a novel framework to model cell developmental dynamics, most notably in the area of single-cell transcriptomics. At present, more than 70 TI methods have been published, and recent benchmarks showed that even state-of-the-art methods only perform well for certain trajectory types but not others.

Results

In this work, we present TinGa, a new TI model that is fast and flexible, and that is based on Growing Neural Graphs. We performed an extensive comparison of TinGa to five state-of-the-art methods for TI on a set of 250 datasets, including both synthetic as well as real datasets. Overall, TinGa improves the state-of-the-art by producing accurate models (comparable to or an improvement on the state-of-the-art) on the whole spectrum of data complexity, from the simplest linear datasets to the most complex disconnected graphs. In addition, TinGa obtained the fastest execution times, showing that our method is thus one of the most versatile methods up to date.

Availability and implementation

R scripts for running TinGa, comparing it to top existing methods and generating the figures of this article are available at https://github.com/Helena-todd/TinGa.
Individualized multi-omic pathway deviation scores using multiple factor analysis
Authors: Rau Andrea , Manansala Regina , Flister Michael J , Rui Hallgeir , Jaffrézic Florence , Laloë Denis , Auer Paul L
Published: July 2020

Malignant progression of normal tissue is typically driven by complex networks of somatic changes, including genetic mutations, copy number aberrations, epigenetic changes, and transcriptional reprogramming. To delineate aberrant multi-omic tumor features that correlate with clinical outcomes, we present a novel pathway-centric tool based on the multiple factor analysis framework called padma. Using a multi-omic consensus representation, padma quantifies and characterizes individualized pathway-specific multi-omic deviations and their underlying drivers, with respect to the sampled population. We demonstrate the utility of padma to correlate patient outcomes with complex genetic, epigenetic, and transcriptomic perturbations in clinically actionable pathways in breast and lung cancer.
The interplay of growth differentiation factor 15 (GDF15) expression and M2 macrophages during prostate carcinogenesis
Authors: Sadasivan Sudha M , Chen Yalei , Gupta Nilesh S , Han Xiaoxia , Bobbitt Kevin R , Chitale Dhananjay A , Williamson Sean R , Rundle Andrew G , Tang Deliang , Rybicki Benjamin A
Published: July 2020

M2 (tumor-supportive) macrophages may upregulate growth differentiation factor 15 (GDF15), which is highly expressed in prostate tumors, but the combined utility of these markers as prognostic biomarkers are unclear. We retrospectively studied 90 prostate cancer cases that underwent radical prostatectomy as their primary treatment and were followed for biochemical recurrence (BCR). These cases also had a benign prostate biopsy at least 1 year or more before their prostate cancer surgery. Using computer algorithms to analyze digitalized immunohistochemically stained slides, GDF15 expression and the presence of M2 macrophages based on the relative density of CD204- and CD68-positive macrophages were measured in prostate: (i) benign biopsy, (ii) cancer and (iii) tumor-adjacent benign (TAB) tissue. Both M2 macrophages (P = 0.0004) and GDF15 (P < 0.0001) showed significant inter-region expression differences. Based on a Cox proportional hazards model, GDF15 expression was not associated with BCR but, in men where GDF15 expression differences between cancer and TAB were highest, the risk of BCR was significantly reduced (hazard ratio = 0.26; 95% confidence interval = 0.09–0.94). In addition, cases with high levels of M2 macrophages in prostate cancer had almost a 5-fold increased risk of BCR (P = 0.01). Expression of GDF15 in prostate TAB was associated with M2 macrophage levels in both prostate cancer and TAB and appeared to moderate M2-macrophage-associated BCR risk. In summary, the relationship of GDF15 expression and CD204-positive M2 macrophage levels is different in a prostate tumor environment compared with an earlier benign biopsy and, collectively, these markers may predict aggressive disease.
Genetic variants in the human leukocyte antigen region and survival of Chinese patients with non-small cell lung carcinoma
Authors: Cheng Lei , Liu Qi , Wang Mengyun , Gu Yanzi , Wang Jialei , Wei Qingyi , Zhang Ruoxin
Published: July 2020

Human leukocyte antigen (HLA) is highly polymorphic, driving antigen presentation, complement cascade and leukocyte maturation against cancer cells. Therefore, we extracted genotyping data in the HLA region from an ongoing Chinese genome-wide association study of non-small cell lung cancer (NSCLC). Using deep sequencing data of 10 689 healthy Han Chinese, we imputed for untyped genetic variants in the HLA region, followed by a two-stage survival analysis of 1531 NSCLC patients. In the discovery stage of 758 patients, we identified 301 out of 15 138 single-nucleotide polymorphisms to be independently associated with overall survival [P < 0.05 and Bayesian false-discovery probability < 0.8]. In further validation of another 773 patients, we confirmed chromosome 6p21, rs241424 (located at intron 3 of TAP2) and rs6457642 as two independent survival predictors. In the combined analysis of 1531 NSCLC patients, rs241424 G>A and rs6457642 C>T were associated with a hazards ratio of 1.26 [95% confidence interval (CI) = 1.14–1.40 and P = 4.04 × 10−6] and 0.76 (95% CI = 0.66–0.87 and P = 1.16 × 10−4), respectively. The analysis of publically available ChIP-sequencing and Hi-C data found that the rs241424 locus was involved in potential cis-regulatory element by a long-range interaction with the HLA-DQA1 promoter. Additional expression quantitative trait loci analysis showed that the rs241424 G>A change decreased HLA-DQA1 mRNA expression. Furthermore, expression levels of HLA-DQA1 were lower in lung cancer tissues than in adjacent normal tissues, and the lower expression was associated with a worse prognosis for patients with lung adenocarcinoma. Collectively, HLA genetic variants may modulate OS of NSCLC patients, possibly via a mechanism of long-range promoter interaction regulating HLA-DQA1 expression.
Targeting cellular senescence in cancer and aging: roles of p53 and its isoforms
Authors: Beck Jessica , Turnquist Casmir , Horikawa Izumi , Harris Curtis
Published: July 2020

Cellular senescence and the associated secretory phenotype (SASP) promote disease in the aged population. Targeting senescent cells by means of removal, modulation of SASP or through cellular reprogramming represents a novel therapeutic avenue for treating cancer- and age-related diseases such as neurodegeneration, pulmonary fibrosis and renal disease. Cellular senescence is partly regulated by the TP53 gene, a critical tumor suppressor gene which encodes 12 or more p53 protein isoforms. This review marks a significant milestone of 40 years of Carcinogenesis publication history and p53 research and 15 years of p53 isoform research. The p53 isoforms are produced through initiation at alternative transcriptional and translational start sites and alternative mRNA splicing. These truncated p53 isoform proteins are endogenously expressed in normal human cells and maintain important functional roles, including modulation of full-length p53-mediated cellular senescence, apoptosis and DNA repair. In this review, we discuss the mechanisms and functions of cellular senescence and SASP in health and disease, the regulation of cellular senescence by p53 isoforms, and the therapeutic potential of targeting cellular senescence to treat cancer- and age-associated diseases.
Clinical Characteristics, Histopathology, and Tissue Immunolocalization of Chikungunya Virus Antigen in Fatal Cases
Authors: Sharp Tyler M , Keating M Kelly , Shieh Wun-Ju , Bhatnagar Julu , Bollweg Brigid C , Levine Rebecca , Blau Dianna M , Torres Jose V , Rivera Aidsa , Perez-Padilla Janice , Munoz-Jordan Jorge , Sanabria Dario , Fischer Marc , Rivera Garcia Brenda , Tomashek Kay M , Zaki Sherif R
Published: July 2020

Background

Death in patients with chikungunya is rare and has been associated with encephalitis, hemorrhage, and septic shock. We describe clinical, histologic, and immunohistochemical findings in individuals who died following chikungunya virus (CHIKV) infection.

Methods

We identified individuals who died in Puerto Rico during 2014 following an acute illness and had CHIKV RNA detected by reverse transcriptase–polymerase chain reaction in a pre- or postmortem blood or tissue specimen. We performed histopathology and immunohistochemistry (IHC) for CHIKV antigen on tissue specimens and collected medical data via record review and family interviews.

Results

Thirty CHIKV-infected fatal cases were identified (0.8/100 000 population). The median age was 61 years (range: 6 days–86 years), and 19 (63%) were male. Death occurred a median of 4 days (range: 1–29) after illness onset. Nearly all (93%) had at least 1 comorbidity, most frequently hypertension, diabetes, or obesity. Nine had severe comorbidities (eg, chronic heart or kidney disease, sickle cell anemia) or coinfection (eg, leptospirosis). Among 24 fatal cases with tissue specimens, 11 (46%) were positive by IHC. CHIKV antigen was most frequently detected in mesenchymal tissues and mononuclear cells including tissue macrophages, blood mononuclear cells, splenic follicular dendritic cells, and Kupffer cells. Common histopathologic findings were intra-alveolar hemorrhage and edema in the lung, chronic or acute tenosynovitis, and increased immunoblasts in the spleen. CHIKV infection likely caused fatal septic shock in 2 patients.

Conclusions

Evaluation of tissue specimens provided insights into the pathogenesis of CHIKV, which may rarely result in septic shock and other severe manifestations.
Direct Evidence of Active SARS-CoV-2 Replication in the Intestine
Authors: Qian Qun , Fan Lifang , Liu Weicheng , Li Jin , Yue Junqiu , Wang Mingwei , Ke Xianliang , Yin Yan , Chen Quanjiao , Jiang Congqing
Published: July 2020

Background

Currently, there is no direct evidence to prove the active replication of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the intestinal tract and relevant pathological changes in the colon and rectum. We investigated the presence of virions and pathological changes in surgical rectal tissues of a patient with clinically confirmed coronavirus disease 2019 (COVID-19) with rectal adenocarcinoma.

Methods

The clinical data were collected during hospitalization and follow-up of this patient. Quantitative reverse transcriptase–polymerasechain reaction (RT-PCR) was performed on the rectal tissue specimens obtained from surgical resection, succus entericus and intestinal mucosa of ileostomy, and rectal mucosa during follow-up after recovery. Ultrathin sections of surgical samples were observed for SARS-CoV-2 virions using electron microscopy. Histopathological examination was performed using hematoxylin-eosin stain. Immunohistochemical analysis and immunofluorescence were carried out on rectal tissues to evaluate the distribution of SARS-CoV-2 antigen and immune cell infiltrations.

Results

The patient had fever and cough on day 3 postoperatively, was diagnosed with COVID-19 on day 7, and was discharged from the hospital on day 41. RNA of SARS-CoV-2 was detected in surgically resected rectal specimens but not in samples collected 37 days after discharge. Notably, coincident with rectal tissues of surgical specimens testing nucleic acid positive for SARS-CoV-2, typical coronavirus virions in rectal tissue were observed under electron microscopy. Moreover, abundant lymphocytes and macrophages (some were SARS-CoV-2 positive) infiltrating the lamina propria were found with no significant mucosal damage.

Conclusions

We first report the direct evidence of active SARS-CoV-2 replication in a patient’s rectum during the incubation period, which might explain SARS-CoV-2 fecal–oral transmission.
Latent Tuberculosis Infection Increases in Kidney Transplantation Recipients Compared With Transplantation Candidates: A Neglected Perspective in Tuberculosis Control
Authors: Shu Chin-Chung , Tsai Meng-Kun , Lin Shu-Wen , Wang Jann-Yuan , Yu Chong-Jen , Lee Chih-Yuan
Published: July 2020

Background

The prevalence and incidence of latent tuberculosis infection (LTBI) in patients with kidney transplantation remain unclear.

Methods

In this prospective study, we enrolled kidney transplantation candidates (KTCs) and recipients (KTRs) from 2014 to 2018. We defined LTBI as a positive result of QuantiFERON-TB Gold In-tube (QFT). We analyzed the predictors for LTBI acquisition and followed up on QFT assay test for 2 years among those initially without LTBI.

Results

Of 425 patients enrolled, 305 (71.8%) patients belonged to the KTC group and 120 (28.2%) to the KTR group. The initial QFT showed positive results in 32 (10.5%) and 24 (20.0%) patients in the KTC and KTR groups, respectively (P = .009). The QFT response value in patients with LTBI was higher in the KTR group than in the KTC group (1.85 vs 1.06 IU/mL, P = .046). Multivariate logistic regression showed that old age, absence of bacillus Calmette–Guérin (BCG) scar, presence of donor-specific antibody, and KTR group were independent factors for positive LTBI. For participants with initial negative QFT, positive QFT conversion within a 2-year follow-up was higher after kidney transplantation (20%) than in KTCs (5.5%) (P = .034).

Conclusions

This study is the first cohort to follow up LTBI status in patients with kidney transplantation and shows its higher prevalence and incidence in KTRs. It indicates that surveillance of LTBI after renal transplantation is important. In addition to status of kidney transplantation, old age, no BCG vaccination, and positive donor-specific antibody are also positive predictors for LTBI.