bluuebunny/crossref_metadata_2025 huggingface dataset:
Effective calculation of thermophysical properties of composite materials with multiple configurations by asymptotic homogenization technique
Authors: Grigoriev Vasiliy , Zakharov Petr , Akimov Mir
Published: December 2019

In this work a three-scale asymptotic homogenization technique is considered for calculating the thermophysical properties of composite materials with multiple periodic configurations. Heterogenieties of porous structures were considered by the periodic distribution of single cells at the microscale and mesoscale levels. Two effective thermal conductivity coefficients are calculated to obtain an average solution on the global structure. A three-scale algorithm is also compared with the classical two-scale homogenization, where microscale allows all heterogenieties. We provide a numerical experiments which show the efficiency and accuracy for the calculation of heat transfer of composite material with multiple configurations.
Scaling in Super Element Model of Petroleum Reservoirs
Authors: Mazo Alexandr , Potashev Konstantin
Published: December 2019

A feature of the super element two-phase flow model in an oil reservoir is the construction of a solution on computational grids with a spatial step of the order of the distance between wells (hundreds of meters) horizontally and of the order of the total thickness of the reservoir (tens of meters) vertically. To maintain the acceptable accuracy of the solution, the upscaling procedures are performed during the transition from a detailed geological to a large super element computational grid and downscaling during a reverse transition at the local refinement of the solution. The field of absolute permeability and functions of relative phase permeability are subject to upscaling. The downscaling procedure is applied to the grid saturation function on the super element grid to formulate the initial conditions for local refinement of the solution on the detailed computational grid. The paper describes ways to simplify and implement these procedures, taking into account the characteristic features of the geological structure and the process of oil reservoir development.
Finite-element modeling of critical loads of buckling of structures considering of nonlinearity of pre-buckling state
Authors: Repinskii V V , Bakulin V N
Published: December 2019

An approach is proposed to determine the critical loads of buckling, taking into account the geometric nonlinearity of the subcritical stress-strain state of structures. The first stage involves the structure strain-stress state in the context of geometrical non-linearity at some preset loading level. Afterwards the found solution neighborhood is supplemented with linearized non-linear equation system and the solution for the obtained linearized system is found. Following is the second linearization of the initial equation system in the linearized system solution neighborhood, obtained at the previous stage. The condition of equation systems degeneracy obtained after the second linearization causes a generalized eigenvalue problem. The approach is implemented using finite element models for the calculation of shell structural elements.
Analytical matrix solutions of linear ordinary differential equations with constant coefficients
Authors: Vinogradov Y I , Molchanov D B , Bakulin V N
Published: December 2019

The article puts forward a modified finite element method based on decomposition and analytical solution techniques. The algorithm is as follows. A complex structure is divided into simple form sub-regions which involve partial differential equations. Next, the equations are decomposed. The decomposed equation solutions are written using analytical solution formulae. Meanwhile, the finite element size of the method proposed is defined only by the value of an averaging interval of required functions, since ordinary differential equation formulae are analytical. The algorithm has been tested by solving rectangular plate and bicurved shallow shell bending problems. The results proved proper convergence to precise values with increasing number of finite elements.
Data space reflectivity full waveform inversion
Authors: Gadylshin Kirill , Tcheverda Vladimir
Published: December 2019

The full waveform inversion of seismic data aroused the hope to perform simultaneously and in automated way tomography and imaging by solving non-linear least-squares optimization problem. As it has been recognized early, brute force minimization by classical methods is hopeless if low time frequencies are absent in the data. The paper develops a reliable numerical technique for smooth velocity reconstruction via model space decomposition. We present realistic synthetic examples for validating presented algorithm.
Numerical method for recovering the piecewise constant right-hand side function of an elliptic equation from a boundary overdetermination data
Authors: Kh Ivanov D , Kolesov A E , Vabishchevich P N
Published: December 2019

An elliptic problem in an open set Ω is considered with Dirichlet boundary condition on piecewise smooth boundary ∂Ω. The inverse problem is to recover piecewise-constant source term, which means an identification function of an unknown subset D ⊂ Ω. An additional information is taken as Neumann boundary condition, which leads us to consider the inverse problem under Cauchy boundary data. In this work a new computational algorithm for recovery the unknown source term is proposed. The main idea is that the identification function of subset D is replaced by a Heaviside function over the solution of an auxiliary elliptic equation. Then we formulate a minimization problem of a residual for overdetermination data, when a control is taken as the right-hand side of the auxiliary equation. Numerical implementation is based on the finite element method applying the open-source computing platform FEniCS and its package dolfin-adjoint. The capabilities of the given computational algorithm are shown by results of numerical solutions of 2D test problems.
Studying of the stability of the flow rates wells unto errors permeability field identification under conditions of single-phase stationary fluid filtration
Authors: Elesin A V , Sh Kadyrova A , Nikiforov A I
Published: December 2019

The problem of calculating the producing wells flow rates in a two-dimensional reservoir is considered under conditions of stationary single-phase fluid filtration. The permeability field of the reservoir is assumed to be unknown and is determined from the solution of the inverse coefficient problem. The identification of the permeability field is carried by the known values of bottomhole pressure and is reduced to the problem of minimizing the residual function.
Recovery of a piecewise constant lower coefficient of an elliptic equation
Authors: Kolesov A E , Kh Ivanov D , Vabishchevich P N
Published: December 2019

Аннотация. We propose a new algorithm for the recovery of a piecewise constant lower coefficient of an elliptic problem. The inverse problem is reduced to a shape reconstruction problem. The proposed algorithm is based on the minimization of a cost functional where a control function is the right-hand side of an auxiliary elliptic equation for a level set representation of unknown shape. Numerical implementation is based on the finite element method and the open-source computing platform FEniCS and dolfin-adjoint. The performance of the algorithm is demonstrated on computationally simulated data.
Identification of parameters of adaptive time series models
Authors: Polezhaev V. D. , Yusupova K. O.
Published: December 2019

The work is devoted to the study of adaptive models of time series and the development of methods for their construction. The most problematic stage in the implementation of algorithms for time series forecasting methods is the identification of unknown parameters, on which the adequacy of the prediction depends. On the basis of economic data, a number of adaptive models have been studied: using exponential smoothing, Brown, Holt-Winters and Theil-Wage models, which take into account seasonality. It was found that the main difficulties arise in the selection of constant smoothing and the choice of coefficients, since no universal algorithm for their task exists.

The paper proposes a method for integrating the adaptive method and the method of numerical optimization. As an optimization method, the non-gradient method was chosen - the Particle Swarm Optimization (PSO), the use of which provided less error in the final forecast and convergence in all applications. Algorithms for finding the parameters to be identified, and a predictive model based on real data are presented. It is shown that in some cases the proposed model has an advantage over other models of time series.
Numerical identification of the initial condition for parabolic equation
Authors: Vasil’ev V.I. , Kardashevsky M.
Published: December 2019

The authors consider a problem of reconstructing of the initial condition in a parabolic equation through the given value of the unknown function at the final moment of time. To perform a numerical solution of the retrospective inverse problem for a multidimensional parabolic equation it is suggested to use a rapidly converging conjugate gradient method, based on a sequential refinement of the initial condition and a direct problem solution at each iteration. The article provides a discussion on the results of a computational experiment conducted on model problems with exact and quasi-realistic solutions, including random errors for desired overdetermination condition.
Study of alumina sealing of HVOF thermally sprayed WC-Co coatings by sol-gel method
Authors: Amousoltani N , Salimijazi H , Golozar M
Published: December 2019

Tungsten carbide (WC) has been known as a hard and wear resistant material. Thermal spray coatings were used widely to deposit Ni and/or Co based WC. The high-velocity oxy-fuel (HVOF) spraying is one of the best methods among thermal spray processes that creates denser coatings with less pores for high corrosive environments applications. In this study, the effect of alumina sealing process on the HVOF WC-12Co coatings by the Sol-Gel method for corrosion and wear properties at high temperature applications was investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to characterize the morphology and properties of the coatings before and after the sealing process. High temperature wear properties of coatings before and after sealing were tested by ball-on-disk wear tester at 400 °C. The cross- section of the sealed coatings showed that open pores were filled after sol gel. The thickness of the sealed layer was about 14 μm. Results indicated that the sealing process increased the microhardness of coating slightly from 1160 ± 160 to 1250 ± 150 HV. Comparing the results of polarization in 3.5 wt% NaCl solution and wear test showed that the corrosion current density decreased and the wear resistance increased after sealing. A sealed sample with filled open porosity led to recording a higher corrosion resistance (2.9 ± 0.7 μA cm−2) compared to the as sprayed coating (8.90 ± 0.5 μA cm−2). The friction profile of the sealed coating showed reduction of the friction coefficient between 0.25 and 0.5 in comparison to the as- sprayed coating at room temperature (04–0.6). Also, the high temperature wear behavior of the sealed coatings was improved. The weight loss was much lower for the sealed coating (5 mg) than that for the as-sprayed coating (13 mg).
Hydrothermal synthesis of magnetic zeolite P from fly ash and its properties
Authors: Wang Peng , Sun Qi , Zhang Yujiao , Cao Jun
Published: December 2019

Magnetic zeolite P with the spherical form was successfully synthesized from low-grade fly ash via hydrothermal synthesis method. These samples were characterized by XRD, XRF, FTIR, BET, VSM, SEM and TEM. The textural properties of magnetic zeolite P were further studied by N2 adsorption-desorption technique. In addition, the vibrating sample magnetometer study confirmed that the saturation magnetization is 11.99 emu·g−1, indicating that magnetic zeolite P has sufficiently magnetic property to be attracted by a permanent magnet. Moreover, this facile approach to study saturation adsorption capacity and percentage removal of the magnetic zeolite P for Pb (II) and Cu (II) ions might expand the application of magnetic zeolite P in the adsorption of heavy metal ions, and it may be further extended to other magnetic zeolite materials.
Prediction of mechanical-hysteresis behavior and complex moduli using the phase field crystal method with modified pressure controlled dynamic equation
Authors: Em-Udom J , Pisutha-Arnond N
Published: December 2019

Damping materials have been used in numerous engineering applications. The important property that plays a key role in this type of material is a damping capacity which is related to mechanical-hysteresis behavior of viscoelasticity. During the last decade, the phase-field-crystal (PFC) model has emerged as a robust tool to predict various material phenomena. This density-functional-type model has the advantage over a conventional phase-field model in terms of atomistic resolution and molecular dynamics in terms of computational expense. In this work, we propose a method to predict mechanical-hysteresis behavior and its related complex moduli parameters using a modified-pressure-controlled dynamics (MPCD) equation incorporating with the PFC model, denoted as PFC-MPCD method, in a three-dimensional solid structure. We modify the previously proposed pressure-controlled dynamics (PCD) equation by introducing the pressure-time derivative term which allows us to produce the results consistent with the standard linear solid model (SLS) at the broader frequency range. We apply sinusoidal pressure oscillation and compare the results predicted by both models. The results demonstrate that mechanical-hysteresis behavior and complex moduli parameters predicted by PFC-MPCD method are in good agreement with those of SLS model and consistent with numerous experimental observations whereas the results produced by original PCD equation tends to exhibit inaccurate results at the very frequency. We expect that this new PFC-MPCD method can be extended to a more complex system and still be capable to exhibit the accurate mechanical-hysteresis behavior and complex moduli parameters which results in predicting more reliable damping capacity parameter in damping material design.
Flacourtia indica based biogenic nanoparticles: development, characterization, and bioactivity against wound associated pathogens
Authors: Ahmad Farooq , Taj Muhammad Babar , Ramzan Muhammad , Raheel Ahmad , Shabbir Saima , Imran Muhammad , Iqbal Hafiz M N
Published: December 2019

Surface engineered nanoparticles (NPs) are of great attention due to their targeted medical applications. The nature of the functionalized surface plays a vital role in achieving the required functionalities of engineered NPs. Owing to the biofilm formation capabilities of wound associated pathogens, impaired wound healing is a major complication in the medical field. In this context, herein, we report the biogenic synthesis of Flacourtia indica (FI) based NPs, i.e., FI-AgNPs using the aqueous leaf extract of this anti-bacterial herb. The newly developed FI-AgNPs were characterized using various analytical and imaging techniques such as UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The FI-AgNPs showed potent anti-microbial activity and anti-biofilm potential which were examined through a test tube adherence method and congo red agar method. It has been observed that synthesized FI-AgNPs inhibit the formation of a biofilm of observed bacteria, even at a minimum concentration of 80 μgml−1. These findings suggest that synthesized FI-AgNPs could be used against wound associated microbes, especially bacterial coating on medical devices, to prevent antibiotic-resistant biofilm infections. Further development and research are obligatory to decode this skill into preventive and therapeutic strategies.
Nobel laureates join call to reinstate top science post
Authors: Allen Michael
Published: December 2019

More than 12,000 scientists, including Andre Geim, Carlo Rubbia and eight other Nobel-prize-winning physicists, have signed a letter calling on the European Commission (EC) to reinstate a dedicated commissioner for education and research.
'Crisis point' as Trump adminisatrtion weakens research safeguards
Authors: Gwynne Peter
Published: December 2019

The integrity of US government research is under siege and has been significantly weakened during the current administration of Donald Trump.
Quantum of light
Authors: de Castro Moreira Ildeu
Published: December 2019

I recently came across a photograph published in a newspaper in Brazil on 5 May 1925, which depicts an interesting time in the history of physics.
A bloody matter
Authors: Follows Michael
Published: December 2019

In reply to the feature “The physics of blood spatter” by Sidney Perkowitz (October pp43–46), which looked at the use of physics to make the forensic technique of blood-spatter analysis more accurate.
A brusque grilling
Authors: North Anthony
Published: December 2019

In response to two Quanta items describing a chilleddrinks “calculator” and a mathematical model for steak cooking (October p3).
Computational 'pathology' uncovered
Authors: Cartlidge Edwin
Published: December 2019

Scientists who think they have accurately modelled chaotic systems on their computers may need to think again. Researchers in the US and UK have uncovered a “pathology” affecting floating-point arithmetic that introduces significant errors when describing systems that are extremely sensitive to their initial conditions.
Cosmic pioneers win Nobel prize
Authors: Banks Michael
Published: December 2019

James Peebles, Michel Mayor and Didier Queloz have been awarded the 2019 Nobel Prize for Physics for their contributions to cosmology and astronomy, as Michael Banks reports
1. What is topology?
Authors: Earl Richard
Published: December 2019

Topology is now a major area of modern mathematics, but an appreciation of topology came late in the history of mathematics. The word topology—meaning ‘the study of place’—was not coined until 1836. ‘What is topology?’ aims to provide a sense of topology’s ideas and its technical vocabulary. It discusses the concepts of letters being topologically the same or homeomorphic and then moves on to Euler’s formula, which shows that there are only five Platonic solids: tetrahedron, cube, octahedron, dodecahedron, and icosahedron. Early problems in topology included defining what dimension means and point-set topology, which sought to address what it means to be a set or to be a space.
2. Making surfaces
Authors: Earl Richard
Published: December 2019

‘Making surfaces’ considers the shape of surfaces and discusses the work of some of the early topologists, Möbius, Klein, and Riemann. It introduces the torus shape and shows how its Euler number can be calculated along with that of a sphere. It discusses closed surfaces—ones without a boundary—and how they can be divided up into vertices, edges, and faces. It then introduces one-sided surfaces such as the Möbius strip and Klein bottle, which are examples of non-orientable surfaces. The Euler number goes a long way to separating out different surfaces, with the only missing ingredient in the classification the notion of orientability.
3. Thinking continuously
Authors: Earl Richard
Published: December 2019

Many topologists might choose to describe their subject as the study of continuity. There are continuous and discontinuous functions in our everyday routines. ‘Thinking continuously’ aims to provide a more rigorous sense of what continuity entails for real-valued functions of a real variable. It focuses on functions having a single numerical input and a single numerical output. The properties of continuous functions are considered and the boundedness theorem and intermediate value theorem are also explained.
Epilogue
Authors: Earl Richard
Published: December 2019

Topology remains a large, active research area in mathematics. Unsurprisingly its character has changed over the last century—there is considerably less current interest in general topology, but whole new areas have emerged, such as topological data analysis to help analyze big data sets. The Epilogue concludes that the interfaces of topology with other areas have remained rich and numerous, and it can be hard telling where topology stops and geometry or algebra or analysis or physics begin. Often that richness comes from studying structures that have interconnected flavours of algebra, geometry, and topology, but sometimes a result, seemingly of an entirely algebraic nature say, can be proved by purely topological means.
Emerging Technologies for Invasive Insects: The Role of Engagement
Authors: Kokotovich Adam E , Delborne Jason A , Elsensohn Johanna , Burrack Hannah
Published: December 2019

Emerging technologies have the potential to offer new applications for managing invasive insects. While scientific and technological advancements are vital to realizing this potential, the successful development and use of these applications will also largely depend on community and stakeholder engagement. To contribute to a relevant and rigorous envisioning of engagement for emerging technologies for invasive insects (ETII), we begin by reviewing key insights on engagement from three scholarly fields: invasive species management, responsible research and innovation, and ecological risk assessment. Across these fields we glean best practices for engagement for ETII: 1) pursue engagement across decision phases and sectors; 2) select context-appropriate participants and methods; and 3) recognize and navigate engagement-related tensions. We illustrate these best practices by describing an ongoing project that uses engagement to inform risk assessment and broader decision making on biotechnologies being developed to address the Spotted-wing Drosophila (Drosophila suzukii) invasive fruit fly. We describe completed and planned engagement activities designed to identify and prioritize potential adverse effects, benefits, management actions, and research actions of the proposed genetically engineered sterile male, gene drive, and RNAi biotechnologies. In the face of broadening calls for engagement on emerging technologies, this article provides theoretical and empirical insights that can guide future engagement for ETII.
Trauma- and Stress-Induced Craving for Alcohol in Individuals Without PTSD
Authors: Ralevski Elizabeth , Southwick Steven , Petrakis Ismene
Published: December 2019

Aims

The main objective of the study was to compare the differences in craving following trauma and stress scripts in individuals with alcohol dependence (AD) who have experienced trauma but did not meet criteria for post-traumatic stress disorder (PTSD).

Methods

Twenty-eight men and women who participated in a treatment trial were included in this study before starting treatment. All had to meet criteria for AD and had experienced trauma at some point of their lives but were never diagnosed with PTSD. All participants had one laboratory session and were exposed to stress, trauma and neutral scripts randomly assigned. Main measures of craving, anxiety and mood were administered before, during and after each script.

Results

Stress and trauma scripts induced significantly more craving and anxiety than the neutral scripts. Interestingly, stress scripts produced stronger craving and anxiety than the trauma scripts but only with some measures. Stress and trauma scripts produced significantly more fear, anger and sadness and significantly lower ratings of joy and relaxation than the neutral script. Again, there were no differences between stress and trauma scripts for any of the emotional subscales.

Conclusions

Trauma scripts did not result in stronger craving than stress scripts. These findings suggest that trauma in the absence of PTSD diagnosis does not lead to stronger craving for alcohol.
Seed development and its relationship to fruit structure in species of Bromelioideae (Bromeliaceae) with fleshy fruits
Authors: Silva Kleber Resende , Stützel Thomas , Oriani Aline
Published: December 2019

In Bromeliaceae, fruit type and seed morphology have been used to distinguish the subfamilies. We studied seed and fruit development of three species of Bromelioideae (Aechmea bromeliifolia, Billbergia distachia and Neoregelia bahiana) relating seed characters to fruit structure. Aechmea bromeliifolia has few ovules per locule inserted within the apical portion of the ovary and the seeds are larger, with a long chalazal appendage, growing towards the fruit base. In B. distachia and N. bahiana, the ovules are numerous and subapically to centrally inserted in the ovary; the seeds are smaller, with a radial disposition, and the chalazal appendages are short (B. distachia) or absent (N. bahiana). The chalazal appendages grow during seed development, and thus their presence/length may be related to the number of ovules/seeds per locule and to the disposition of the ovules inside the locules. The fruits are berries, and juiciness is promoted by mesocarp cells and by substances secreted inside the locules by the placental obturator at later stages of fruit development. These fruit and seed features are strategies for zoochory and provide evidence that each species studied is dispersed by a different type of animal.
Building façade-level correlates of bird–window collisions in a small urban area
Authors: Riding Corey S , O’Connell Timothy J , Loss Scott R
Published: December 2019

Urbanization increasingly exposes birds to multiple sources of direct anthropogenic mortality. Collisions with buildings, and windows in particular, are a top bird mortality source, annually causing 365–988 million fatalities in the United States. Correlates of window collision rates have been studied at the scale of entire buildings and in relation to the surrounding landscape, and most studies have only assessed correlates for all birds combined without considering season- and species-specific risk factors. In Stillwater, Oklahoma, USA, we conducted bird collision surveys at 16 buildings to assess building structural-, vegetation-, and land cover-related collision correlates. Unlike past studies, we focused at the scale of individual building façades, and in addition to considering correlates for total collisions, we assessed correlates for different seasons and separately for 8 collision-prone species. Several façade-related features, including proportional glass coverage, façade length, and façade height, were positively associated with total collisions and collisions for most separate seasons and species. Total collisions were also greater at alcove-shaped façades than flat, curved, and portico-shaped façades. We found that collision correlates varied among seasons (e.g., surrounding lawn cover important in summer and fall, but not spring) and among species (e.g., surrounding impervious cover positively and negatively related to collisions of Painted Bunting [Passerina ciris] and American Robin [Turdus migratorius], respectively). Given the importance of glass proportion, collision reduction efforts should continue to focus on minimizing and/or treating glass surfaces on new and existing buildings. Our species- and season-specific assessments indicate that management of some collision risk factors may not be equally effective for all seasons and species. Future research, policy, and management that integrates information about collision risk for all bird species and seasons, and at multiple scales from building façades to the surrounding landscape, will be most effective at reducing total mortality from bird–window collisions.
Fecal stress, nutrition and reproductive hormones for monitoring environmental impacts on tigers (Panthera tigris)
Authors: Mondol Samrat , Booth Rebecca K , Wasser Samuel K
Published: December 2019

Non-invasive stress and nutritional hormone analysis in relation to ecological and other biological indices have tremendous potential to address environmental disturbance impacts on wildlife health. To this end, we examined the relation between glucocorticoid (GC) and thyroid (T3) hormone indices of disturbance and nutritional stress in response to ACTH and TSH challenges in captive tigers, as well as how reproductive hormones vary by sex and reproductive condition. Glucocorticoid, thyroid, progesterone and androgen assays conducted on high-performance liquid chromatography separated fractions of biologically relevant fecal extracts revealed high cross-reactivity of these assays for their respective biologically relevant fecal hormone metabolites. Both adrenal and thyroid hormone metabolites were elevated in response to ACTH and TSH challenges. However, the adrenal and thyroid hormone responses to ACTH challenge were concurrent, whereas the adrenal response to TSH challenge was delayed relative to thyroid hormone elevation in both males and females. The concurrently elevated T3 in response to ACTH may serve to raise metabolic rate to maximize use of GC-mobilized glucose, whereas the relatively delayed GC rise following TSH challenge may be a response to glucose depletion due to increased metabolic rate associated with elevated T3. Progesterone, testosterone and androstenedione hormone metabolites were significantly elevated during gestation compared to lactation in a female monitored from conception through early lactation. Results suggest that the glucocorticoid, thyroid and reproductive hormone assays we tested can accurately measure the stress, nutrition and reproductive response from tiger feces, providing useful non-invasive tools to assess physiological responses to environmental stressors and their reproductive consequences in the wild.
Cardiac monocytes and macrophages after myocardial infarction
Authors: Peet Claire , Ivetic Aleksandar , Bromage Daniel I , Shah Ajay M
Published: December 2019

Improvements in early interventions after acute myocardial infarction (AMI), notably, the increased use of timely reperfusion therapy, have increased survival dramatically in recent decades. Despite this, maladaptive ventricular remodelling and subsequent heart failure (HF) following AMI remain a significant clinical challenge, particularly because several pre-clinical strategies to attenuate remodelling have failed to translate into clinical practice. Monocytes and macrophages, pleiotropic cells of the innate immune system, are integral in both the initial inflammatory response to injury and subsequent wound healing in many tissues, including the heart. However, maladaptive immune cell behaviour contributes to ventricular remodelling in mouse models, prompting experimental efforts to modulate the immune response to prevent the development of HF. Seminal work in macrophage biology defined macrophages as monocyte-derived cells that are comprised of two populations, pro-inflammatory M1 macrophages and reparative M2 macrophages, and initial investigations into cardiac macrophage populations following AMI suggested they aligned well to this model. However, more recent data, in the heart and other tissues, demonstrate remarkable heterogeneity and plasticity in macrophage development, phenotype, and function. These recent insights into macrophage biology may explain the failure of non-specific immunosuppressive strategies and offer novel opportunities for therapeutic targeting to prevent HF following AMI. Here, we summarize the traditional monocyte-macrophage paradigm, experimental evidence for the significance of these cells in HF after AMI, and the potential relevance of emerging evidence that refutes canonical models of monocyte and macrophage biology.
Use of esophageal stents to relieve dysphagia during neoadjuvant therapy prior to esophageal resection: a systematic review
Authors: Ahmed O , Bolger J C , O’Neill B , Robb W B
Published: December 2019

Esophageal cancer stenting offers symptomatic relief for patients suffering from dysphagia. There are limited data to support their use to relieve dysphagia and improve nutrition during neoadjuvant therapy with some concern that they may negatively impact oncological outcomes. The aim of this systematic review was to quantify the impact of esophageal stents on outcomes prior to resection with curative intent. A literature search was performed using Embase, Medline, PubMed, PubMed Central, the Cochrane library for articles pertaining to esophageal stent use prior to or during neoadjuvant chemotherapy or chemoradiotherapy in patients planned for curative esophagectomy. Data extracted included basic demographics, clinical, nutritional and oncologic outcomes. A total of 9 studies involving 465 patients were included. Esophageal stent use resulted in a significant improvement in mean dysphagia scores in the immediate post stent period but failed to demonstrate any positive changes in weight, body mass index (BMI) or albumin. Only 33% of stented patients ultimately progressed to potential curative surgical resection and stents were associated with reduced R0 resection rates and lower overall survival. This systematic review shows that, although esophageal stenting is associated with improvements in dysphagia during neoadjuvant therapy, their effect on improving patient nutritional status is less clear and they may be associated with poorer long-term oncological outcomes. Stents should be used with caution in patients who are being considered for potentially curative resection of esophageal malignancies and other strategies of nutritional supplementation should be considered.
Selective Sampling with Information-Storage Constraints
Authors: Jehiel Philippe , Steiner Jakub
Published: December 2019

A memoryless agent can acquire arbitrarily many signals. After each signal observation, she either terminates and chooses an action, or she discards her observation and draws a new signal. By conditioning the probability of termination on the information collected, she controls the correlation between the payoff state and her terminal action. We provide an optimality condition for the emerging stochastic choice. The condition highlights the benefits of selective memory applied to the extracted signals. Implications—obtained in simple examples—include (i) confirmation bias, (ii) speed-accuracy complementarity, (iii) overweighting of rare events, and (iv) salience effect.
Hyperbaric oxygen therapy in the prevention and management of tracheal and oesophageal anastomotic complications
Authors: Tapias Luis F , Wright Cameron D , Lanuti Michael , Muniappan Ashok , Deschler Daniel , Mathisen Douglas J
Published: December 2019

OBJECTIVES

Failure of anastomotic healing is a morbid complication after airway or oesophageal surgery. Hyperbaric oxygen therapy (HBOT) has been used extensively in the management of complex wound-healing problems. We demonstrate the use of HBOT to rescue at-risk anastomoses or manage anastomotic failures in thoracic surgery.

METHODS

Retrospective review of 25 patients who received HBOT as part of the management of tracheal or oesophageal anastomotic problems during 2007–2018. HBOT was delivered at 2 atm with 100% oxygen in 90-min sessions.

RESULTS

Twenty-three patients underwent airway resection and reconstruction while 2 patients underwent oesophagectomy. There were 16 (70%) laryngotracheal and 7 (30%) tracheal resections. Necrosis at the airway anastomosis was found in 13 (57%) patients, partial dehiscence in 2 (9%) patients and both in 6 (26%) patients. HBOT was prophylactic in 2 (9%) patients. Patients received a median of 9.5 HBOT sessions (interquartile range 5–19 sessions) over a median course of 8 days. The airway anastomosis healed in 20 of 23 (87%) patients. Overall, a satisfactory long-term airway outcome was achieved in 19 (83%) patients; 4 patients failed and required reoperation (2 tracheostomies and 1 T-tube). HBOT was used in 2 patients after oesophagectomy to manage focal necrosis or ischaemia at the anastomosis, with success in 1 patient. Complications from HBOT were infrequent and mild (e.g. ear discomfort).

CONCLUSIONS

HBOT should be considered as an adjunct in the management of anastomotic problems after airway surgery. It may also play a role after oesophagectomy. Possible mechanisms of action are rapid granulation, early re-epithelialization and angiogenesis.
Explanations for economic difficulties among old-age pensioners previously on disability pension
Authors: Polvinen Anu , Laaksonen Mikko , Rantala Juha , Palomäki Liisa-Maria , Kuivalainen Susan
Published: December 2019

Background

This study looks at how previous disability retirement is associated with economic difficulties in covering the costs of everyday basic necessities in old age, and the extent to which the differences in economic difficulties between old-age pensioners with previous disability pension and other old-age pensioners are mediated by health, income and life satisfaction.

Methods

The survey data includes 2227 retirees aged 63–85 who were receiving old-age pension in 2017. A quarter of them had received a disability pension before their old-age pension. Economic difficulties were measured through a subjective assessment of how difficult it was to cover the following necessities: food, housing, medication, health services, transport, phone and internet use. The odds ratios and their 95%-confidence intervals were analyzed with ordered logistic regression models.

Results

Old-age pensioners with previous disability retirement experienced more economic difficulties in covering cost of necessities than other old-age pensioners. The differences were especially large among those with a mental diagnosis. Health, pension income and life satisfaction attenuated the differences slightly. The fully adjusted odds ratio for having economic difficulties in covering the cost of medicine and health care among old-age pensioners with previous disability retirement due to mental disorders was 2.15 (95% CI 1.44–3.22) compared to other old-age pensioners without previous disability retirement.

Conclusions

Preventing disability retirement among working-age people diminishes the risk of economic difficulties in old age. More attention should be focussed especially on those with a high risk of disability retirement due to mental disorders.
The association between parity, CVD mortality and CVD risk factors among Norwegian women and men
Authors: Kravdal Øystein , Tverdal Aage , Grundy Emily
Published: December 2019

Background

Several studies have shown that women and men with two children have lower mortality than the childless, but there is less certainty about mortality, including CVD mortality, at higher parities and meagre knowledge about factors underlying the parity–mortality relationship.

Methods

The association between parity and CVD mortality was analyzed by estimating discrete-time hazard models for women and men aged 40–80 in 1975–2015. Register data covering the entire Norwegian population were used, and the models included a larger number of relevant sociodemographic control variables than in many previous studies. To analyze the relationship between parity and seven CVD risk factors, logistic models including the same variables as the mortality models were estimated from the CONOR collection of health surveys, linked to the register data.

Results

Men (but not women) who had four or more children had higher mortality from CVD than those with two, although this excess mortality was not observed for the heart disease sub-group. Overweight, possibly in part a result of less physical activity, seems to play a role in this. All CVD risk factors except smoking and alcohol may contribute to the relatively high CVD mortality among childless.

Conclusions

Childbearing is related to a number of well-known CVD risk factors, and becoming a parent or having an additional child is, on the whole, associated with lower—or at least not higher—CVD mortality in Norway. However, for men family sizes beyond three children are associated with increased CVD mortality, with risks of overweight one possible pathway.
Soil characteristics and land-use drive bacterial community assembly patterns
Authors: Barnett Samuel E , Youngblut Nicholas D , Buckley Daniel H
Published: December 2019

Land-use and soil characteristics drive variation in soil community composition, but the influences of these factors on dispersal and community assembly at regional scale remain poorly characterized. Land-use remains a consistent driver of soil community composition even when exhibiting patchy spatial distribution at regional scale. In addition, disturbed and early successional soils often exhibit stochastic community assembly patterns. These observations suggest local community composition is influenced by dispersal and assembly from regional species pools. We examined bacterial community assembly within agricultural cropland, old-field, and forested sites across 10 landscapes in the region around Ithaca, New York (USA). We found that the Sloan neutral model explained assembly well at regional scale (R2 = 0.763), but that both soil pH and land-use imposed selection that shaped community composition. We show that homogeneous selection was a dominant assembly process with respect to both soil pH and land-use regime, but that these two factors interacted in their effects on bacterial community assembly. We conclude that bacterial community assembly at a regional scale is driven by dispersal from regional species pools and local selection on the basis of soil pH and other soil characteristics that vary with land-use.
Listeria monocytogenes in sliced cheese and ham from retail markets in southern Brazil
Authors: Maia Darla Silveira Volcan , Haubert Louise , Würfel Simone de Fátima Rauber , Kroning Isabela Schneid , Cardoso Marisa Ribeiro de Itapema , Lopes Graciela Völz , Fiorentini Ângela Maria , da Silva Wladimir Padilha
Published: December 2019

The aims of this study were to evaluate the occurrence of Listeria monocytogenes and Salmonella spp. in sliced cheese and ham from retail markets in southern Brazil, as well as to perform molecular characterization and to assess the antimicrobial resistance profile of the isolates. Samples (n = 160) of sliced cheese and ham were collected at retail level from the city of Pelotas, Brazil. The isolation of L. monocytogenes and Salmonella spp. was performed and the isolates were confirmed by PCR, submitted to antimicrobial susceptibility testing and pulsed-field gel electrophoresis (PFGE). Listeria monocytogenes was found in 9.4% (15/160) of the samples. All L. monocytogenes isolates were positive for the prs, inlA, inlC and inlJ genes. Salmonella spp. was not isolated. Regarding the antimicrobial susceptibility, one (6.6%) L. monocytogenes isolate was resistant to streptomycin and four (26.6%) to clindamycin. Macrorestriction analysis with ApaI and AscI enzymes yielded two major PFGE groups I and II. All L. monocytogenes isolates showed virulence genes, and some of them were resistant to clinically used antimicrobials, representing a risk to public health. Moreover, PFGE patterns with high similarity were visualized in L. monocytogenes isolates at different times, demonstrating adaptability of the pathogen at retail level in the region.
Regulatory role of pyruvate-sensing BtsSR in biofilm formation by Escherichia coli K-12
Authors: Ogasawara Hiroshi , Ishizuka Toshiyuki , Yamaji Kotaro , Kato Yuki , Shimada Tomohiro , Ishihama Akira
Published: December 2019

Pyruvate, the key regulator in connection of a variety of metabolic pathways, influences transcription of the Escherichia coli genome through controlling the activity of two pyruvate-sensing two-component systems (TCSs), BtsSR and PyrSR. Previously, we identified the whole set of regulatory targets of PyrSR with low-affinity to pyruvate. Using gSELEX screening system, we found here that BtsSR with high-affinity to pyruvate regulates more than 100 genes including as many as 13 transcription factors genes including the csgD gene encoding the master regulator of biofilm formation. CsgD regulates more than 20 target genes including the csg operons encoding the Curli fimbriae. In addition, we identified the csgBAC as one of the regulatory targets of BtsR, thus indicating the involvement of two pyruvate-dependent regulatory pathways of the curli formation: indirect regulation by CsgD; and direct regulation by BtsR. Based on the findings of the whole set of regulatory targets by two pyruvate-sensing BtsR and PyrR, we further propose an innovative concept that the pyruvate level-dependent regulation of different gene sets takes place through two pyruvate-sensing TCS systems, high-affinity BtsSR and low-affinity PyrSR to pyruvate.
Mutational analysis of the flavinylation and binding motifs in two protein targets of the flavin transferase ApbE
Authors: Bertsova Yulia V , Serebryakova Marina V , Anashkin Victor A , Baykov Alexander A , Bogachev Alexander V
Published: December 2019

Many flavoproteins belonging to three domain types contain an FMN residue linked through a phosphoester bond to a threonine or serine residue found in a conserved seven-residue motif. The flavinylation reaction is catalyzed by a specific enzyme, ApbE, which uses FAD as a substrate. To determine the structural requirements of the flavinylation reaction, we examined the effects of single substitutions in the flavinylation motif of Klebsiella pneumoniae cytoplasmic fumarate reductase on its modification by its own ApbE in recombinant Escherichia coli cells. The replacement of the flavin acceptor threonine with alanine completely abolished the modification reaction, whereas the replacements of conserved aspartate and serine had only minor effects. Effects of other substitutions, including replacing the acceptor threonine with serine, (a 10–55% decrease in the flavinylation degree) pinpointed important glycine and alanine residues and suggested an excessive capacity of the ApbE-based flavinylation system in vivo. Consistent with this deduction, drastic replacements of conserved leucine and threonine residues in the binding pocket that accommodates FMN residue still allowed appreciable flavinylation of the NqrC subunit of Vibrio harveyi Na+-translocating NADH:quinone oxidoreductase, despite a profound weakening of the isoalloxazine ring binding and an increase in its exposure to solvent.
Beneficial and detrimental effects of processed dietary fibers on intestinal and liver health: health benefits of refined dietary fibers need to be redefined!
Authors: Singh Vishal , Vijay-Kumar Matam
Published: December 2019

Consumption of processed foods—which are generally composed of nutritionally starved refined ingredients—has increased exponentially worldwide. A rise in public health awareness that low fiber intake is strongly linked to new-age disorders has spurred food manufacturers to fortify processed foods with refined dietary fibers (RDFs). Consumption of whole foods rich in natural fibers undoubtedly confers an array of health benefits. However, it is not clear whether RDFs extracted from the whole plant, kernel, and fruit peels exert similar physiological effects to their naturally occurring counterparts. Recent studies caution that RDFs are not universally beneficial and that inappropriate consumption of RDFs may risk both gastrointestinal and liver health. Herein, we briefly summarize the beneficial and detrimental effects of RDFs on digestive health and discuss the contribution of metabolites derived from microbial fermentation of RDFs in driving such positive or negative health outcomes.