bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic stability of anisotropic fiber-reinforced plate
Authors: Eshmatov Bakhtiyor , Abdikarimov Rustam , Komilova Kholida , Safarbayeva Nigora
Published: June 2021

The dynamic stability problem of an anisotropic fiber-reinforced plate under increasing compressing load is considered in a geometrically nonlinear formulation using the Kirchhoff-Love’s shell theory. The problem is solved using the Bubnov-Galerkin method based on a polynomial approximation of the deflections in combination with a numerical method based on quadrature formulas. For a wide range of variations of physical, mechanical, and geometrical parameters, the dynamic behavior of the plate is studied.
Strength assessment of the body of a weight checking wagon type 640-VPV
Authors: Ruzmetov Yadgor , Adilov Nodir , Sultonov Shokhruk
Published: June 2021

In the article, necessary to design and build new and modern weighing wagons to replace the outdated ones, but this will take some time. Thus, before the construction of new wagons and the optimal use of existing wagons, it is necessary to extend their service life. Extension of the service life of weighing wagons involves determining the current technical condition and residual resources of these wagons. For this purpose, a survey and analysis of the main bearing elements and structural parameters of the bodies of the weighing wagons were carried out.
Optimization of the terminal operating mode during the formation of a container block train
Authors: Rasulov Marufdjan , Masharipov Masud , Ismatullaev Azizbek
Published: June 2021

Currently, container shipping plays an important role in international logistics. Terminals handle containers between different modes of transport and are a key element in supply chains. The quality of transport services, in general, depends on the technical and technological parameters of container terminals. At the same time, the task is to optimize the operating mode of the container terminal to reduce logistics costs. This article presents the results of a study of the traffic flows of terminals adjacent to the Tashkent regional railway junction stations, obtained based on timing observations on the unloading of containers arriving at the terminal by road for shipment by container trains. Based on these observations, the regularities of the distribution of the probabilities of the arrival of containers at the terminal and the time of servicing vehicles by a gantry crane were established. With the help of the established patterns, the main indicators were selected that characterize the quality of the container terminal functioning. A mathematical model has been developed and an algorithm for finding the optimal operating mode of a container terminal when forming a container block train. As the results of calculations have shown, the volume of logistics costs for the operation of a container terminal depends on the type and quantity of used handling equipment and the number of supply of fitting wagons to loading and unloading routes.
Vibration damping composition polymer materials and coatings for engineering purpose
Authors: Negmatov Soyibjon , Ulmasov T , Navruzov Farxod , Jovliyev S
Published: June 2021

To develop and create effective vibration-damping composite polymer materials (VDСPM) with high viscoelastic and strength properties, the choice of research objects to increase durability reduces vibration of parts and structures of machines consequently, the noise level in industrial premises is stated and substantiated. A method is described for studying the viscoelastic properties, adhesive strength, microhardness, impact strength of polymer coatings, and compositions based on them, filled with organomineral ingredients. The results of studies of the viscoelastic and physicomechanical properties of polymer composite materials based on epoxy polymers and an organomineral filler - rubber powder are presented. Based on complex analyzes and the obtained results of the study of the physicomechanical and viscoelastic properties of materials, several effective compositions of vibration-damping polymer materials using rubber powder have been developed.
Intelligent signal detectors with random moment of appearance in rail lines monitoring systems
Authors: Aripov Nazirjon , Sadikov Azamat , Ubaydullayev Saidazim
Published: June 2021

The article discusses the issues of building intelligent receivers of pulsed signals with an unknown arrival time without restrictions on the value of the signal-to-noise ratio under the influence of a complex of interfering factors. Using recurrent methods for detecting disturbances of random processes and an algorithm of cumulative sums, the problem of synthesizing algorithms for detecting Markov signals with random moments of appearance against the background of various combinations of destabilizing factors acting in control systems for the states of rail lines in normal and shunt operating modes is solved. To assess the efficiency of detecting a random signal by the method of cumulative sums, statistical modeling of the specified algorithm was carried out.
Structure and properties of the modified diffusion nitride-oxide surface layer
Authors: Eshkabilov Kholikul , Berdiyev Sherzod
Published: June 2021

To combine the processes of gas nitriding and oxidation in water vapor, the effects of the atmospheric nitrogen potential in dissociated ammonia on the formation of surface diffusion nitride phases are studied.

Modification of the surface nitride layer with oxygen was carried out by oxidation of the nitride zone at the second stage of obtaining an oxycarbonitride layer.

The corrosion and wear-resistant properties of the nitride-oxide layer t of the lowest nitride layer are investigated, depending on the phase changes in the nitride layer after oxidation. The distributions of the elements in the nitride-oxide layer are determined, and the nature of the formation of the modified surface layer under the combination of gas nitriding with subsequent oxidation in water vapor is established.
Vibrations of dam–plate of a hydro-technical structure under seismic load
Authors: Tukhtaboev A , Leonov Sergey , Turaev Fozil , Ruzmetov Kudrat
Published: June 2021

In present paper, the problem of the vibration of a viscoelastic dam-plate of a hydro-technical structure is investigated, based on the Kirchhoff-Love hypothesis in the geometrically nonlinear statement. This problem is reduced to a system of nonlinear ordinary integro-differential equations by using the Bubnov-Galerkin method. The resulting system with a weakly-singular Koltunov-Rzhanitsyn kernel is solved using a numerical method based on quadrature formulas. The behavior of the viscoelastic dam-plate of hydro-technical structure is studied for the wide ranges of physical, mechanical, and geometrical material parameters.
Running quality assessment of a passenger car produced in the Republic of Uzbekistan
Authors: Zairova Dilfuza , Kadirov Mukhammad Ayubkhan , Khojiev Nodirali , Khikmatov Farkhod , Shokuchkorov Kurbonnazar
Published: June 2021

The article discusses a topical issue regarding the replenishment of the passenger car fleet with promising and comfortable passenger cars. To determine the quality assessment of the passenger carriage, a check was carried out for compliance with the standards for the smoothness of the carriage. Based on the main technical parameters of the new passenger carriage, the main calculated values were determined with and without taking into account the payload. Comparing the results obtained with the highest permissible values, it was found that the quality indicators of the passenger carriage model 61-920 manufactured in the Republic of Uzbekistan do not exceed the permissible values and meet the requirements.
Les aléas naturels intégrés à la sûreté nucléaire
Authors: Crampon Cécile
Published: June 2021

Comment assurer la sûreté nucléaire face aux aléas climatiques ? Il s’agit de s’appuyer sur le retour d’expérience (REX) d’installations nucléaires qui ont expérimenté des événements majeurs en France et à l’étranger, mais aussi de prendre en compte l’ensemble des aléas pouvant se rencontrer sur le territoire français, avec une méthodologie rigoureuse pour des aléas d’intensité très élevée. Le point avec Vincent Rebour, chef du service de caractérisation des sites et des aléas naturels à l’Institut de radioprotection et de sûreté nucléaire (IRSN), et Hervé Cordier, chef du groupe doctrine agressions, à la Direction de l’ingénierie et des projets nouveau nucléaire (DIPNN) chez EDF (Présentation issue du webinaire
organisé par la Sfen, le 15 décembre 2020.).
Effect of government subsidies on supply chain decision-making and coordination in the context of COVID-19
Authors: Yang Sen , Qian Wuyong
Published: June 2021

Considering the two-stage supply chain composed of a leading retailer and a manufacturer under the background of covid-19 epidemic, the retailer determines the anti-epidemic effort level and bears the corresponding costs, and the manufacturer determines the cost sharing rate under the coordination strategy. This paper analyzes the pricing decision, anti-epidemic effort level and cost sharing rate of supply chain under different government subsidy measures and coordination strategies. From the perspective of Stackelberg game, we find that under the background of epidemic situation, government subsidies can improve the level of social welfare; the improvement of marginal income of anti-epidemic efforts is conducive to obtain a higher level of anti-epidemic efforts and social welfare; Within the reasonable marginal revenue range of anti-epidemic efforts, the coordination strategy can improve the retailers’ anti-epidemic efforts and social welfare level, and the government can obtain the maximum anti-epidemic efforts and social welfare level by subsidizing manufacturers with cost sharing.
Vitamin C: Ein Hoffnungsträger in Prävention wie Therapie der COVID-19-Infektion?
Authors: Stange Rainer
Published: June 2021

Laut Nationaler Verzehrsstudie II aus dem Jahr 2008 übertrifft die Vitamin-C-Aufnahme im Median in Deutschland die DGE-Empfehlungen deutlich. Vitamin C ist das beliebteste Vitaminsupplement, auch bei ausreichender Aufnahme mit der Nahrung. Eine mangelnde Aufnahme wird jedoch meist weniger wahrgenommen.

Bislang existieren wenige Studien mit kleinen Studienkollektiven zur Vitamin-C-Gabe bei COVID-19. Die Ergebnisse verweisen auf einen möglichen Nutzen einer hochdosierten Vitamin-C-Gabe hinsichtlich der Mortalität, der akuten Imflammation sowie der Krankenhausaufenthaltsdauer. Im Clinical-Trials-Register finden sich 45 registrierte Studien, sodass mit weiteren Veröffentlichungen gerechnet werden kann.

Patienten, bei denen die Wahrscheinlichkeit für eine ungenügende Vitamin-C-Versorgung groß erscheint, sollte in der Prophylaxe besondere Aufmerksamkeit gelten. Auf Dauer sollten praktisch leicht nutzbare Elemente aus der Ernährungstherapie aufgezeigt werden.
Presión en la reparación de manguito rotador con suturas transóseas y Mason-Allen modificado
Authors: Fernández Julio José Contreras , Osses Oscar Sepúlveda , Esper Nicolás Prado , Silva Ricardo Guzmán , Verdugo Rodrigo Liendo , Rex Francisco Soza
Published: June 2021

Objetivo Comparar el promedio de curva de presión de contacto y el porcentaje de presión de contacto residual final en la interfase tendón-huella de una reparación transósea (TO) realizada con nudos cruzados y una configuración Mason-Allen modificada (MAM).

Métodos Se utilizaron ocho hombros de cordero para simular una rotura de manguito rotador. Se midió la presión con un sensor digital. Se registró la presión basal durante la aplicación de carga cíclica y al final de la intervención. Se compararon dos reparaciones: dos túneles TOs con nudos cruzados (TOCs) (n = 4) y dos puntos MAMs (n = 4) utilizando suturas MaxBraid #2 (Zimmer Biomet, Warsaw, IN, EEUU). Se realizaron 1.000 ciclos, con una frecuencia de 2 Hz y una carga de 30 N. Se utilizó el test de t de Student, y se consideraron significativos valores de p < 0,05.

Resultados El promedio de curva de presión de contacto en las piezas que fueron reparadas con suturas TOCs fue de 86,01 ±  8,43%, mientras que con MAM fue de 73,28 ±  12,01% (p < 0,0004). El promedio del porcentaje residual al final del ciclado fue de 71,57% para suturas TOCs y de 51,19% para MAM (p < 0,05).

Conclusión La reparación TOC presenta mayor promedio de curva de presión de contacto y mayor porcentaje de presión de contacto residual final en la interfase tendón-huella que la reparación con sutura MAM luego de carga cíclica estandarizada, lo que podría traducirse en una mejor cicatrización del tendón.

Nivel de Evidencia Estudio de ciencia básica.
BCL11A Polymorphism in Egyptian Children with β-Thalassemia: Relation to Phenotypic Heterogeneity
Authors: Salah Nouran Y. , Ali Heba G. A. , Bassiouny Noha , Salem Lamya , Taha Sara I. , Youssef Mariam K. , Annaka Layla , Barakat Noha M.
Published: June 2021

Fetal hemoglobin (HbF) is a potent genetic modifier of β-thalassemia phenotype. B-cell lymphoma 11A (BCL11A) gene results in significant silencing of HbF. The aim of this study was to assess the prevalence of different BCL11A genotypes among a cohort of Egyptian children with β-thalassemia and to correlate them to HbF and clinical severity score. Eighty-two children with β-thalassemia (aged 12.95 ± 3.63 years) were recruited from the Pediatric Hematology Clinic, Ain Shams University. They were divided based on the clinical severity of β-thalassemia into three subgroups: 20 mild (24.4%), 24 moderate (29.3%), and 38 severe (46.3%). Age, gender, age of diagnosis, initial HbF level, transfusion history, and history of splenectomy were assessed. Anthropometric measures, signs of anemia and hemosiderosis, and the severity score were determined. Laboratory investigations such as complete blood picture, ferritin, and single gene polymorphism genotyping of the rs11886868 were also performed. Our findings showed that 16 children had CC genotype (19.5%), 38 had TC genotype (46.3%), and 28 had TT genotype (34.1%) of the rs#. β-thalassemia children with TT genotype had significantly higher severity scoring than the other two groups (p < 0.001). Moreover, mean initial HbF was found to be lower in children with TT genotype followed by TC and CC genotypes (p < 0.001). Increased γ-globin expression associated with BCL11A gene polymorphism is associated with better clinical severity of β-thalassemia.
X-Linked Myotubular Myopathy: A Novel Mutation Expanding the Genotypic Spectrum of a Phenotypically Heterogeneous Myopathy
Authors: Carvalho Andreia , Costa Carmen , Pinto Miguel , Taipa Ricardo , Gonçalves Ana , Oliveira Márcia E. , Ferreira Sofia , Ribeiro Joana Afonso
Published: June 2021

X-linked myotubular myopathy (XLMTM), a centronuclear congenital myopathy secondary to pathogenic variants in the MTM1 gene encoding myotubularin, is typically recognized for its classic and severe phenotype which includes neonatal hypotonia, severe muscle weakness, long-term ventilator dependence, markedly delayed gross motor milestones with inability to independently ambulate, and a high neonatal and childhood mortality. However, milder congenital forms of the condition and other phenotypes are recognized. We describe a 6-year-old boy with a mild XLMTM phenotype with independent gait and no respiratory insufficiency even in the neonatal period. The child has a hemizygous novel splice site variant in the MTM1 gene (c.232–25A > T) whose pathogenicity was confirmed by cDNA studies (exon 5 skipping) and muscle biopsy findings. We also compared the phenotype of our patient with the few reported cases that presented a mild XLMTM phenotype and no respiratory distress at birth, and discussed the potential mechanisms underlying this phenotype such as the presence of residual expression of the normal myotubularin transcript.
Multilayer beam splitter advances light sheet fluorescence microscopy
Authors: Frank Jodi Ackerman
Published: June 2021

Technique extends field of view and improves uniformity while maintaining resolution.
Marcus’ electron transfer rate revisited via a Rice-Ramsperger-Kassel-Marcus analogue: A unified formalism for linear and nonlinear solvation scenarios
Authors: Wang Yao , Su Yu , Xu Rui-Xue , Zheng Xiao , Yan YiJing
Published: June 2021

In the pioneering work by R. A. Marcus, the solvation effect on electron transfer (ET) processes was investigated, giving rise to the celebrated nonadiabatic ET rate formula. In this work, on the basis of the thermodynamic solvation potentials analysis, we reexamine Marcus’ formula with respect to the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. Interestingly, the obtained RRKM analogue, which recovers the original Marcus’ rate that is in a linear solvation scenario, is also applicable to the nonlinear solvation scenarios, where the multiple curve-crossing of solvation potentials exists. Parallelly, we revisit the corresponding Fermi’s golden rule results, with some critical comments against the RRKM analogue proposed in this work. For illustration, we consider the quadratic solvation scenarios, on the basis of physically well-supported descriptors.
Detection of radiocarbon dioxide with double-resonance absorption spectroscopy
Authors: Tan Yan-dong , Cheng Cun-feng , Sheng Dong , Hu Shui-ming
Published: June 2021

Fast and accurate quantitative detection of 14CO2 has important applications in many fields. The optical detection method based on the sensitive cavity ring-down spectroscopy technology has great potential. But currently it has difficulties of insufficient sensitivity and susceptibility to absorption of other isotopes/impurity molecules. We propose a stepped double-resonance spectroscopy method to excite 14CO2 molecules to an intermediate vibrationally excited state, and use cavity ringdown spectroscopy to probe them. The two-photon process significantly improves the selectivity of detection. We derive the quantitative measurement capability of double-resonance absorption spectroscopy. The simulation results show that the double-resonance spectroscopy measurement is Doppler-free, thereby reducing the effect of other molecular absorption. It is expected that this method can achieve high-selectivity detection of 14CO2 at the sub-ppt level.
Active tuning of elastic wave propagation in a piezoelectric metamaterial beam
Authors: Zhao Xi-Ning , Yang Xiao-Dong , Zhang Wei , Pu Huayan
Published: June 2021

In this paper, an active control strategy is employed to actively tune the vibration and wave propagation properties in a piezoelectric metamaterial beam. The piezoelectric actuator and sensor are periodically arranged along the piezoelectric metamaterial beam. By using the extended Hamilton principle, the governing equations for the fully coupled piezoelectric metamaterial beam are obtained. The negative proportional feedback control strategy is introduced to achieve the periodical active stiffness for the piezoelectric metamaterial beam. The band structures and natural frequencies of the proposed periodic structure are derived by the transfer matrix method, and the spectral element method is applied as numerical validation. The influences of the feedback control gain ratio, length ratio, and the number of the unit cells on natural frequencies and bandgaps are discussed. Results indicate that the natural frequencies of the system are reduced with the increase in the feedback control gain ratio and length ratio. In addition, multiple bandgaps can be generated by using the negative proportional feedback control strategy. It is found that bandwidths can be obviously broadened by selecting the proper feedback control gain ratio and length ratio. The theoretical and numerical results show that the vibration and wave propagation properties of the proposed piezoelectric metamaterial beam can be controlled by using the negative proportional feedback control strategy.
The area localized coupled model for analytical mean flow prediction in arbitrary wind farm geometries
Authors: Starke Genevieve M. , Meneveau Charles , King Jennifer R. , Gayme Dennice F.
Published: June 2021

This work introduces the area localized coupled (ALC) model, which extends the applicability of approaches that couple classical wake superposition models and atmospheric boundary layer models to wind farms with arbitrary layouts. Coupling wake and top–down boundary layer models is particularly challenging since the latter requires averaging over planform areas associated with turbine-specific regions of the flow that need to be specified. The ALC model uses Voronoi tessellation to define this local area around each turbine. A top–down description of a developing internal boundary layer is then applied over Voronoi cells upstream of each turbine to estimate the local mean velocity profile. Coupling between the velocity at hub-height based on this localized top–down model and a wake model is achieved by enforcing a minimum least-square-error in mean velocity in each cell. The wake model in the present implementation takes into account variations in wind farm inflow velocity and represents the wake profile behind each turbine as a super-Gaussian function that smoothly transitions between a top-hat shape in the region immediately following the turbine to a Gaussian profile downstream. Detailed comparisons to large-eddy simulation (LES) data from two different wind farms demonstrate the efficacy of the model in accurately predicting both wind farm power output and local turbine hub-height velocity for different wind farm geometries. These validations using data generated from two different LES codes demonstrate the model's versatility with respect to capturing results from different simulation setups and wind farm configurations.
Charge injection capacity of ferroelectric microelectrodes for bioelectronic applications
Authors: Becker Maximilian T.
Published: June 2021

We analyze the extracellular stimulation current and the charge injection capacity (CIC) of microelectrodes coated with an insulating layer to prevent toxic electrochemical effects in bioelectronic applications. We show for a microelectrode coated with an insulating ferroelectric layer that the ferroelectric polarization current contributes to the extracellular stimulation current. Depending on the remanent polarization Pr of the ferroelectric, the polarization current in the switching regime can increase the CIC by up to two orders of magnitude as compared to the commonly used extracellular capacitive stimulation with microelectrodes that are coated with a dielectric layer.
High-energy single-longitudinal-mode mid-infrared optical parametric amplifier seeded with sheet optical parametric oscillator
Authors: Wang Xiaohan , Jia Kunpeng , Yao Hongquan , Zhou Jun , Lv Xinjie , Zhao Gang , Xie Zhenda , Zhu Shining
Published: June 2021

Mid-infrared (MIR) radiation is essential for remote gas sensing, ranging, and lidar applications, where high pulse energy and narrow linewidth are the keys to the high sensitivity over long distance. However, complex optical and electronic locking schemes are normally required to achieve both features at the same time. Here, we demonstrate pulse-pumped single-longitudinal-mode (SLM) MIR generation using a microresonator seed in the form of a sheet optical parametric oscillator (SOPO). The SOPO features a sub-coherence-length thickness of 400 µm, which enables SLM and high-energy oscillation using cavity phase matching. Its output around 1.55 µm is seeded into an optical parametric amplifier and locks the MIR output in SLM at 3.38 µm. In a simple and compact setup, up to 21% conversion efficiency and 22% slope efficiency are measured with a MIR output energy of 54 µJ. This SLM MIR source with the SOPO seed greatly reduces the system size and is compatible for further integration for field-deployable devices and thus has broad applications in the field of remote gas sensing.
The variation of C4F7N, C5F10O, and their decomposition components in breakdown under different pressures
Authors: Fu Yuwei , Chen Chi , Wang Chuang , Yang Lei , Zhang Zaiqin , Wang Tingting , Luo Bing
Published: June 2021

The decomposition characteristics of C4F7N and C5F10O are basic to understand their insulating and arc-quenching performance, and the decomposition products are related to the equipment discharge fault and insulation state. A chemical kinetic model is employed to study the variation of C4F7N, C5F10O, and their decomposition components under different pressures. The results show that the molar fraction and recombination rate of C5F10O are higher than those of C4F7N, and high pressure has larger influence on the molar fraction and recovery rate of C5F10O than those of C4F7N, so C5F10O presents a better molecular recovery characteristic and dielectric strength than C4F7N at high pressures.
Understanding end-of-life care in Australian hospitals
Authors: Mitchell Imogen , Lacey Jeanette , Anstey Matthew , Corbett Cathy , Douglas Carol , Drummond Christine , Hensley Michel , Mills Amber , Scott Caroline , Slee Jo-Anne , Weil Jennifer , Scholz Brett , Burke Brandon , D’Este Catherine
Published: June 2021

Objective To explore end-of-life care in the ward and intensive care unit (ICU) environment in nine Australian hospitals in a retrospective observational study. Methods In total, 1693 in-hospital deaths, 356 in ICU, were reviewed, including patient demographics, advance care plans, life-sustaining treatments, recognition of dying by clinicians and evidence of the palliative approach to patient care. Results Most patients (n = 1430, 84%) were aged ≥60 years, with a low percentage (n = 208, 12%) having an end-of-life care plan on admission. Following admission, 82% (n = 1391) of patients were recognised as dying, but the time between recognition of dying to death was short (ICU (staying 4–48 h) median 0.34 days (first quartile (Q1), third quartile (Q3): 0.16, 0.72); Ward (staying more than 48 h) median 2.1 days (Q1, Q3: 0.96, 4.3)). Although 41% (n = 621) patients were referred for specialist palliative care, most referrals were within the last few days of life (2.3 days (0.88, 5.9)) and 62% of patients (n = 1047) experienced active intervention in their final 48 h. Conclusions Late recognition of dying can expose patients to active interventions and minimises timely palliative care. To attain alignment to the National Consensus Statement to improve experiences of end-of-life care, a nationally coordinated approach is needed. What is known about the topic? The majority of Australian patient deaths occur in hospitals whose care needs to align to the Australian Commission on Safety and Quality in Health Care’s National Consensus Statement, essential elements of safe and high-quality end-of-life care. What does this paper add? The largest Australian study of hospital deaths reveals only 12% of patients have existing advance care plans, recognition of death is predominantly within the last 48 h of life, with 60% receiving investigations and interventions during this time with late symptom relief. What are the implications for practitioners? Given the poor alignment with the National Consensus Statement, a nationally coordinated approach would improve the patient experience of end-of-life care.
Additives and polymer composition influence the interaction of microplastics with xenobiotics
Authors: Hummel Darius , Fath Andreas , Hofmann Thilo , Hüffer Thorsten
Published: June 2021

Environmental context The effects of the presence of polymer additives and polymeric structure on sorption of xenobiotics to microplastics remain unclear. Our results combined data from experimental sorption batch experiments using three environmentally relevant model sorbates with confocal microscopy. This provides clear evidence that both factors play a major role in sorption strength and the underlying sorption process, affecting sorption onto the particle surface and partitioning into the bulk polymer. Abstract Microplastics are particulate contaminants of global concern. Interactions of microplastics with organic contaminants are frequently studied with commercially available polymer materials as surrogates. The influence of the polymer structure (i.e. internal 3D polymer geometry and monomer chain length) and the presence of additives on their interactions with xenobiotics remains unclear. This work investigates sorption of three sorbates of environmental concern to two polyamide (PA) and two polyvinyl chloride (PVC) sorbents of different molecular composition and additive content, respectively. Sorption was studied using complementary data from sorption isotherms and confocal laser-scanning microscopy. The additives in PVC increased sorption affinity owing to an increased sorbent hydrophobicity and a higher void volume within the polymer. Surface area normalisation indicated surface adsorption for unplasticised PVC and absorption for 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH)-plasticised PVC, which were confirmed using confocal laser-scanning microscopy. The strong sorption to PA was mainly driven by hydrogen-bond interactions. The contribution depended on the molecular features of the sorbent and the sorbate. Confocal laser-scanning microscopy showed that PA6 was taking up more sorbate into its bulk polymer matrix than PA12, the two being different in their chemical composition. This difference could be attributed to the higher swelling capability of PA6. The results emphasise that the molecular structure of the polymer and the presence of additives have to be taken into consideration when sorption of organic substances to plastics is investigated.
Succession of marine fouling community influences the associated mobile fauna via physical complexity increment
Authors: Vicente Vanessa S. , Ferreira Ana P. , Peres Pedro A. , Siqueira Silvana G. L. , Leite Fosca P. P. , Vieira Edson A.
Published: June 2021

Sessile communities provide habitat for feeding, reproduction and protection to a diverse mobile fauna. Along succession, the growth and overgrowth of three-dimensional sessile organisms generate structural complexity and microhabitats for mobile organisms. Most studies focus on one species or group of the sessile fauna as a habitat provider, but here we investigated the whole community, using fouling communities as a model. We tested the hypothesis that they would gain structural complexity along succession, resulting in an increase in abundance and biomass, and compositional changes of the associated mobile groups. The organisms were obtained from communities growing on PVC plates left in the water for 6, 9 and 12 months. Early succession fouling communities (6 months) were mostly flatter, dominated by encrusting bryozoans and more empty space and cover of delicate hydrozoans and filamentous algae. Advanced-succession fouling communities (9 and 12 months) showed a biomass increment and compositional changes by the increased cover of structurally complex sessile organisms, such as arborescent bryozoans and sponges. Mobile groups showed higher abundance and biomass, and a different composition at later stages. Thus, our results emphasise how the structural complexity provided by fouling organisms and the changes over succession may mediate the changes in the associated mobile fauna.
Single-molecule calorimeter and free energy landscape
Authors: Wang Yi , Tang Zhuodong , Chen Hong-Yuan , Wang Wei , Tao Nongjian , Wang Hui
Published: June 2021

Significance

Measuring the complete thermodynamic profile of a single molecule reveals unparalleled advantages in the biological realm. We develop a single-molecule calorimeter with plasmonic imaging and optical tweezer by probing the thermal fluctuations of single nanoparticles linked to the substrate via the single-molecule binding pair. This uncovers the complete thermodynamic information for single binding events and identifies the equilibrium state and energetic components of the free energy landscape, suggesting possibilities for offering high-throughout analysis of single-molecule interactions.
Cucurbit aphid-borne yellows virus (Cucurbit aphid-borne yellows).
Authors: Lecoq Hervé , Desbiez Cécile , Schoeny Alexandra
Published: June 2021

Cucurbit aphid-borne yellows virus (CABYV) was first isolated in southern France in 1988. It causes, mostly in cucurbits, more or less severe yellowing diseases according to the season and cultivar. CABYV infects several weed species and is readily transmitted in a persistent manner by ubiquitous aphids that provide an efficient means of invasiveness worldwide. Symptoms of CABYV are similar to other biotic or abiotic disorders and dating first occurrences of the virus was difficult until appropriate diagnostic methods were developed. There is evidence that CABYV is becoming more frequent in areas where it was reported earlier (France, Spain and parts of Asia) and that it might have been recently introduced into new areas (Northern Europe, South America). Therefore, CABYV may be considered as potentially invasive both in places where it has not yet been reported and where it is already present. CABYV is not regulated or on an alert list.
East Asian Passiflora virus.
Authors: Iwai Hisashi
Published: June 2021

East Asian Passiflora virus (EAPV) is a potyvirus that infects passion fruit Passiflora edulis. It can produce mosaic symptoms on leaves and severely malformed and woody fruits (Iwai et al., 1996). It is currently found in Japan, Taiwan and Peninsular Malaysia, although its global distribution is not yet clear.
Echinochloa crus-pavonis (gulf cockspur grass).
Authors: Kaufman Sylvan
Published: June 2021

Echinochloa crus-pavonis is a clump forming grass native to the Americas that is now found in Africa, Asia, Oceania and Europe. It is likely its spread was facilitated by rice cultivation around the world, as it is a frequent contaminant of rice grains. It listed as invasive and a weed of agriculture. E. crus-pavonis is widely documented as a significant weed of rice fields. It is an 'occasional weed of cultivation' in Australia. It is considered invasive in Cuba, Paraguay, Cameroon, the Ivory Coast, Nigeria, Italy and California, USA.
Cowpea mild mottle virus (angular mosaic of beans).
Authors: Brown Judith K.
Published: June 2021

Cowpea mild mottle virus (CPMMV) infects a wide range of cultivated legumes. It causes severe mosaic and/or necrosis on the leaves, stems and pods of beans (Phaselous), cowpea (Vigna) and soyabean (Glycine max). Yield losses of 64-80% have been recorded in groundnuts in Kenya (Bock et al., 1976, 1977) and 10-100% in soyabean in Brazil and Argentina (Brown and Rodrigues, 2017). The virus is transmitted in a non-persistent manner by the whitefly, Bemisia tabaci. CPMMV is considered endemic to Africa, but has spread to India, South-East Asia, South America, the Caribbean, Puerto Rico and Mexico. Introduction of the virus to Puerto Rico, and possibly also Mexico, is thought to have been through infected seed from South America and perhaps Africa. The virus poses a threat to soyabean production in the USA and, if introduced into mainland USA, CPMMV has potential to spread through seed, on infected ornamental or vegetable transplants, and by the viruliferous whitefly, itself if previously associated with a virus-infected host.
Armillaria novae-zelandiae.
Authors: Hood Ian
Published: June 2021

Armillaria novae-zelandiae is a white rot wood decay fungus and root disease pathogen that occurs in a number of countries in the Southern Hemisphere and in parts of tropical and subtropical Asia. It is not known to have been introduced to these regions, where it is presumed to be indigenous. Its designation as "invasive" is based on its propensity to establish colonies and disease centres in disease-free areas by dispersal of basidiospores from "toadstool" fruit bodies that appear on wood during the winter months. As a wood decomposer fungus A. novae-zelandiae contributes beneficially to carbon and nutrient recycling. Like many other Armillaria species it is recognized by characteristic white mycelial fans or ribbons produced beneath host bark and by its bootlace-like rhizomorphs by which it spreads vegetatively from colonized buried woody material or stump root systems to infect living host plants.Armillaria novae-zelandiae was the cause of substantial disease losses in plantations of Pinus radiata and orchards of kiwifruit vines (Actinidia deliciosa) in New Zealand from the 1970s to the 1990s. Its importance has since declined with changes in patterns of crop management, although it remains widely distributed. Much research into its control was undertaken during this period. In eastern states in Australia, A. novae-zelandiae is a minor cause of root disease in natural and planted forests, where it is of lesser importance than Armillaria luteobubalina. Its impact in other regions is unknown, but it has not been associated with reports of significant disease. Risk of unintended international spread appears to be low to negligible but should not be discounted. If intercepted, isolates of A. novae-zelandiae may be identified by laboratory culture testing or more rapidly and precisely by molecular sequencing procedures. A. novae-zelandiae is listed in the EPPO Global Database and features in the United States Department of Agriculture Agricultural Research Service fungal databases. It is considered a risk organism in Hawai'i.
Candidatus Phytoplasma solani (Stolbur phytoplasma).
Authors: Quaglino Fabio
Published: June 2021

Phytoplasmas are cell-wall-less plant pathogenic bacteria of the class Mollicutes, which inhabit the phloem sieve tubes of plants and have been associated with several hundred diseases affecting economically important crops. Over the past few decades 'Candidatus Phytoplasma solani', belonging to the 16SrXII-A ribosomal subgroup, has been found to cause a range of plant diseases in different agro-ecosystems in many countries in Europe and the eastern Mediterranean area and a number of others all over the world. It is thought likely that it has always been present, at least in its European range, but has only been noticed in recent years. Diseases caused include bois noir in grapevines, stolbur in tomatoes, potatoes and other wild and cultivated plants, maize redness, lavender decline, and yellowing, reddening, decline, dwarfism, leaf malformation and degeneration diseases of other plants. 'Ca. P. solani' is usually transmitted from plant to plant by the polyphagous insect vector Hyalesthes obsoletus (Cixiidae) which, although it can complete its life cycle on only a small number of plant species, feeds on a much wider range. Recent studies have demonstrated the presence of additional insect vectors of this phytoplasma in Europe, such as Reptalus panzeri in Serbia, possibly R. quinquecostatus in Serbia and France, and Anaceratagallia ribauti in Austria. This scenario highlights the extreme complexity of the ecology of both 'Ca. Phytoplasma solani' and its insect vectors, underlying the difficulty in studying the epidemiology of diseases associated with this pathogen and in developing efficient control strategies. 'Ca. Phytoplasma solani' is also transmitted by parasitic plants and by grafting and vegetative propagation of infected host plants; it can be spread when host plants are transported by people. In the European Union it is listed as a harmful organism necessitating restrictions on the import of plants in the family Solanaceae.
Metallurgical joining of aluminium and copper using resistance spot welding: microstructure and mechanical properties
Authors: Zare Mohammad , Pouranvari Majid
Published: June 2021

This paper investigates the melting phenomena, joining mechanism, microstructure evolution, and mechanical properties of the Al/Cu dissimilar joints made using resistance spot welding. A metallurgical bonding between Al and Cu is achieved via the reaction-diffusion between liquid Al and solid Cu (i.e. brazing mechanism). The reaction layer was featured by the in-situ formation of an ultra-thin Cu-rich Al–Cu intermetallic compound at the joint interface, on-cooling formation of coarse and thick θ-Al2Cu as the primary phase for hyper-eutectic solidification and formation of ultrafine lamellar α-Al/θ-Al2Cu eutectic structure. It is shown that the peak load and energy absorption of the Al/Cu joints are controlled by the effective length of the solid/liquid reaction zone and the thickness of the θ-Al2Cu primary solidification phase.
Does perceived wellness influence technical–tactical match performance? A study in youth international rugby using partial least squares correlation analysis
Authors: Ramírez‐López Carlos , Till Kevin , Weaving Dan , Boyd Andy , Peeters Alexis , Beasley Grant , Bradley Sam , Giuliano Pierosario , Venables Charlie , Jones Ben
Published: June 2021

The purpose of this study was to determine the relationship between matchday wellness status and a technical–tactical performance construct during rugby match‐play. One hundred and thirty‐three male rugby union players (73 forwards and 60 backs) from five under‐18 national squads who participated in the under‐18 Six Nations competition completed a subjective wellness questionnaire on each matchday morning. Players subjectively rated each item (sleep quality, fatigue, muscle soreness, stress and mood) on a five‐point Likert scale to calculate their daily wellness status (i.e. difference between matchday and baseline perceived wellness). Technical–tactical performance during match‐play was quantified by coding individual key performance indicators (e.g. number of carries, number of tackles). Partial least squares correlation analysis (PLSCA) was employed to compute the latent variables of perceived wellness status (X matrix) and technical–tactical performance (Y matrix) for each player observation (n = 271). The latent variables are a construct of each variable group, enabling higher dimensional data to be visualised more simply. Linear mixed‐effect models were later conducted to assess the relationships between the latent variables. The effect of perceived wellness status on technical–tactical performance was statistically significant in forwards (p = .042), not statistically significant in backs (p = .120) and accounted for 4.9% and 1.9% variance in the technical–tactical performance construct, respectively. The findings of this study suggest that perceived wellness status can influence technical–tactical match performance, but the practical significance of these findings should be interpreted with caution given the amount of variance in technical–tactical performance accounted by the models.
Confronting mitigation deterrence in low-carbon scenarios
Authors: Grant Neil , Hawkes Adam , Mittal Shivika , Gambhir Ajay
Published: June 2021

Carbon dioxide removal (CDR) features heavily in low-carbon scenarios, where it often substitutes for emission reductions in both the near-term and long-term, enabling temperature targets to be met at lower cost. There are major concerns around the scale of CDR deployment in many low-carbon scenarios, and the risk that anticipated future CDR could dilute incentives to reduce emissions now, a phenomenon known as mitigation deterrence. Here we conduct an in-depth analysis into the relationship between emissions reduction and emissions removal in a global integrated assessment model. We explore the impact of CDR on low-carbon scenarios, illustrating how the pathway for the 2020s is highly sensitive to assumptions around CDR availability. Using stochastic optimisation, we demonstrate that accounting for uncertainty in future CDR deployment provides a strong rationale to increase rates of mitigation in the 2020s. A 20% chance of CDR deployment failure requires additional emissions reduction in 2030 of 3–17 GtCO2. Finally, we introduce new scenarios which demonstrate the risks of mitigation deterrence and the benefits of formally separating CDR and emissions reduction as climate strategies. Continual mitigation deterrence across the time-horizon leads to the temperature goals being breached by 0.2–0.3 °C. If CDR is treated as additional to emissions reduction, up to an additional 700–800 GtCO2 can be removed from the atmosphere by 2100, reducing end-of-century warming by up to 0.5 °C. This could put sub-1.5 °C targets within reach but requires that CDR is additional to, rather than replaces, emission reductions.
Spatial-temporal patterns of ambient fine particulate matter (PM2.5) and black carbon (BC) pollution in Accra
Authors: Alli Abosede S , Clark Sierra N , Hughes Allison , Nimo James , Bedford-Moses Josephine , Baah Solomon , Wang Jiayuan , Vallarino Jose , Agyemang Ernest , Barratt Benjamin , Beddows Andrew , Kelly Frank , Owusu George , Baumgartner Jill , Brauer Michael , Ezzati Majid , Agyei-Mensah Samuel , Arku Raphael E
Published: June 2021

Sub-Saharan Africa (SSA) is rapidly urbanizing, and ambient air pollution has emerged as a major environmental health concern in growing cities. Yet, effective air quality management is hindered by limited data. We deployed robust, low-cost and low-power devices in a large-scale measurement campaign and characterized within-city variations in fine particulate matter (PM2.5) and black carbon (BC) pollution in Accra, Ghana. Between April 2019 and June 2020, we measured weekly gravimetric (filter-based) and minute-by-minute PM2.5 concentrations at 146 unique locations, comprising of 10 fixed (∼1 year) and 136 rotating (7 day) sites covering a range of land-use and source influences. Filters were weighed for mass, and light absorbance (10−5m−1) of the filters was used as proxy for BC concentration. Year-long data at four fixed sites that were monitored in a previous study (2006–2007) were compared to assess changes in PM2.5 concentrations. The mean annual PM2.5 across the fixed sites ranged from 26 μg m−3 at a peri-urban site to 43 μg m−3 at a commercial, business, and industrial (CBI) site. CBI areas had the highest PM2.5 levels (mean: 37 μg m−3), followed by high-density residential neighborhoods (mean: 36 μg m−3), while peri-urban areas recorded the lowest (mean: 26 μg m−3). Both PM2.5 and BC levels were highest during the dry dusty Harmattan period (mean PM2.5: 89 μg m−3) compared to non-Harmattan season (mean PM2.5: 23 μg m−3). PM2.5 at all sites peaked at dawn and dusk, coinciding with morning and evening heavy traffic. We found about a 50% reduction (71 vs 37 μg m−3) in mean annual PM2.5 concentrations when compared to measurements in 2006–2007 in Accra. Ambient PM2.5 concentrations in Accra may have plateaued at levels lower than those seen in large Asian megacities. However, levels are still 2- to 4-fold higher than the WHO guideline. Effective and equitable policies are needed to reduce pollution levels and protect public health.
On the construction of a complete Kähler-Einstein metric with negative scalar curvature near an isolated log-canonical singularity
Authors: Fang Hanlong , Fu Xin
Published: June 2021

In this short note we are concerned with the Kähler-Einstein metrics near cone type log canonical singularities. By two different approaches, we construct a Kähler-Einstein metric with negative scalar curvature in a neighborhood of the cone over a Calabi-Yau manifold which is complete towards the vertex. This provides a local model for the further study of the global Kähler-Einstein metrics on singular varieties. In the first approach, we show that the singularity is uniformized by a complex ball and hence the induced metric from the Bergman metric of the ball is the desired one. In the second approach, we obtain a Kähler-Einstein metric with the desired properties by Calabi Ansatz. At last, we show that the obtained metrics are the same.