bluuebunny/crossref_metadata_2025 huggingface dataset:
Bacteria Adhesion on Polydimethylsiloxane Surfaces Impacted by Material Viscoelasticity or Surface Chemistry?
Authors: Pan Fei , Altenried Stefanie , Liu Mengdi , Hegemann Dirk , Bülbül Ezgi , Moeller Jens , Schmahl Wolfgang W. , Maniura-Weber Katharina , Ren Qun
Published: July 2020

Among nosocomial infections, materials associated infections are the most frequent and severe due to biofilm formation. To prevent bacterial colonization, understanding the underlying interaction between bacteria and surface is fundamental. Herein we focused on studying how material viscoelasticity and physicochemistry can influence bacterial adhesion, using polydimethylsiloxane (PDMS) as a model material. To delineate the impact caused by bulk material from interfacial physicochemical properties, a 2 nm PDMS-like polymer layer was coated onto PDMS surfaces of different stiffness to confer comparable surface chemical properties, while retaining similar viscoelasticity for coated and uncoated PDMS species. Although the uncoated samples displayed increasing interfacial adhesion force with the decreasing Young's modulus, the nanolayer coating ensured comparable forces independent of material stiffness. The Gram negative strains Escherichia coli and Pseudomonas aeruginosa and the Gram positive strain Staphylococcus epidermidis were found to adhere respectively in similar numbers on the coated surfaces of different PDMS species, whereas the amount on the uncoated surfaces increased several fold with the decreasing modulus. The similar adhesion behaviour was noticed for abiotic polystyrene beads of similar size to bacteria, demonstrating that the interfacial chemistry of the PDMS rather than the material viscoelasticity plays a crucial role in bacterial adhesion. 
Soft coatings, a new antimicrobial strategy for biomaterials?
Authors: Vigué Annabelle , Vautier Dominique , Hardouin Julie , Arntz Youri , Ball Vincent , Senger Bernard , Jouenne Thierry , Ploux Lydie
Published: July 2020

Fighting microbial biofilms on biomaterials is usually addressed by incorporating antimicrobial agents. Nevertheless, as usual in the natural life, intrinsic properties of the material surface can also be a complementary approach. They may drastically reduce the quantity of adhered microorganisms and the remaining microorganisms can be treated with classical antimicrobial agents. Mechanical properties of material surfaces recently emerged as a possible way to impact biofilm formation, but many questions have still to be elucidated so far.

We have especially investigated whether hydrogel and non-hydrogel soft and stiff films may differently impact, microbial behavior and biofilm formation. The films have been thoroughly characterized in terms of viscoelasticity, hydration and chemistry. Microbial mobility, adhered quantity and production of organelles such as pili have been specifically investigated. Surface properties, especially mechanical ones, have been thoroughly characterized. The study has been conducted with yeast (Candida albicans) and bacteria species (Escherichia coli) as models. Our results reveal that the stiffness differently impacts the amount and mobility of the adhered cells according to the nature of the film.  These softness- and hydration-dependent microbial phenomena also vary with bacteria and yeast species.

Finally, this confirms the relevance of using some soft coatings to prevent biofilm formation on a material but also clarifies the risks to get opposite effects as desired if other crucial surface properties have not been associated.
Antimicriobial Activity of Silver-Nanoparticles studied by Scanning Probe Microscopy
Authors: Caniglia Giada , Heinzmann Anna , Sportelli Maria Chiara , Valentini Antonio , Cioffi Nicola , Kranz Christine
Published: July 2020

Biofilms are well-organized sessile communities which exhibit an increased tolerance against antimicrobial and antibiotic treatments in comparison with their planktonic counterparts. Biofilms are ubiquitous and due to their high resilience, the problem with contamination of medical implants leads to serious health problems [1]. Within the last decades, novel therapies to prevent the formation of biofilms have been developed and, among others, antimicrobials based on metal nanoparticles (NPs) have been intensively studied [2], due to their ability to reduce biofilm formation. Silver nanoparticles (AgNPs) are known to be effective antimicrobial agents, as silver(I) has the ability to penetrate the cell and produce oxidative stress via the generation of reactive oxygen species (ROS) [3]. To understand the release mechanism of silver(I) ions, scanning electrochemical probe microscopy such as scanning electrochemical microscopy (SECM) is highly suitable.

In this contribution, biocompatible AgNPs-fluoropolymer (Ag-CFx) composite films, prepared by ion beam sputtering (IBS) deposition [4], are investigated in respect to silver(I) release associated to the swelling of the antimicrobial film. The mechanism of the silver(I) release is studied real-time by scanning electrochemical microscopy (SECM) in combination with square-wave stripping voltammetry and the relation between controlled silver(I) release and the swelling of Ag-CFx films will be presented, combining electrochemical techniques and atomic force microscopy (AFM).

 

References

[1] G.C. Anderson, et al. Innate and Induced Resistance Mechanisms of Bacterial Biofilms. In Bacterial Biofilms; Romeo, T., Ed.; Springer Berlin Heidelberg: Berlin, Heidelberg, 2008; pp 85–105.

[2] M.C. Sportelli, et al. Nano-Antimicrobials Based on Metals. In Novel Antimicrobial Agents and Strategies; John Wiley & Sons, Ltd, 2014; pp 181–218.

[3] N. Durán, et al. Nanomedicine, 2016, 12(3), 789-799.

[4] M.C. Sportelli, et al. Sci. Rep. 2017, 7 (1), 11870.

 

Acknowledgements

Financial support is acknowledged from European Union’s 2020 research and innovation program under the Marie Sklodowska-Curie Grant Agreement No. 813439.
Bacterial nanotubes and their role as bacterial nanowires in Pseudomonas aeruginosa biofilms
Authors: ma luyan
Published: July 2020

Microbial nanowires are nanofilaments that could offer an extracellular electron transfer (EET) pathway linking the bacterial respiratory chain to external surfaces, such as oxidized metals in the environment and engineered electrodes in renewable energy devices. Filaments proposed to function as nanowires have been reported in multiple bacteria, yet it remains largely unclear about the composition and electron transfer mechanism of bacterial nanowires. Pseudomonas aeruginosa is an environmental and electrochemically active bacterium. In this study, we found nanotube-like extracellular filaments in P. aeruginosa biofilms, which were bacterial membrane extensions similar to the nanowires reported in Shewanella oneidensis. Remarkably, conductive probe atomic force microscope showed measurable conductivity of these extracellular filaments, suggesting that they may function as nanowires in P. aeruginosa. Our results also indicated that the electron shuttle pyocyanin significantly affected the conductivity of P. aeruginosa nanowires, suggesting that the electron transfer mechanism of P. aeruginosa nanowires was different from S. oneidensis. Furthermore, factors that impact biofilm formation, such as flagella, type IV pili, and exopolysaccharides, were not essential for nanowires formation, while affect the formation and length of nanowires of P. aeruginosa. Taken together, this is the first report that investigated the role of electron shuttle on the conductivity of nanowires and factors that affected nanowires formation.
BiofilmQ, a software tool for quantiative image analysis of microbial biofilm communities
Authors: Jeckel Hannah , Hartmann Raimo , Jelli Eric , Drescher Knut ,   BiofilmQ team
Published: July 2020

Biofilms are now considered to be the most abundant form of microbial life on Earth, playing critical roles in biogeochemical cycles, agriculture, and health care. Phenotypic and genotypic variations in biofilms generally occur in three-dimensional space and time, and biofilms are therefore often investigated using microscopy. However, the quantitative analysis of microscopy images presents a key obstacle in phenotyping biofilm communities and single-cell heterogeneity inside biofilms. Here, we present BiofilmQ, a comprehensive image cytometry software tool for the automated high-throughput quantification and visualization of 3D and 2D community properties in space and time. Using BiofilmQ does not require prior knowledge of programming or image processing and provides a user-friendly graphical user interface, resulting in editable publication-quality figures. BiofilmQ is designed for handling fluorescence images of any spatially structured microbial community and growth geometry, including microscopic, mesoscopic, macroscopic colonies and aggregates, as well as bacterial biofilms in the context of eukaryotic hosts.
Bacterial Differentiation in Oral Multi-Species Biofilm Models Using Confocal Raman Microscopy
Authors: Kriem Lukas , Rupp Steffen , Wright Kevin , Ccahuana-Vasquez Renzo
Published: July 2020

Objectives: Confocal Raman microscopy can give inside knowledge on the composition and structure of biofilms and give some understanding on the strain’s role in the development and then maturation of biofilm structures. This information can then be helpful in understanding the impact of structure on both disease formation and the impact of therapies on biofilms. While different techniques like CLSM real-time PCR, SEM and others have been used for biofilm analysis successfully, confocal Raman microscopy has the advantage to be non-destructive and can thus consider the construction of biofilms over time.

Methods: S.oralis (DSM20066), V.dispar (DSM20735) and A.denticolens (DSM20671) were cultivated in brain-heart infusion broth under anaerobic conditions (37°C, 80% N2, 15% CO2, 5% H2) for 96h. Biofilms were formed on hydroxyapatite discs under the same conditions by using the static ‘Zürich’ model. A Renishaw inVia Qontor instrument was used for confocal Raman analysis of planktonic cells and biofilms (532nm Laser, 50mW laser power, 1s exposure time, 15 scans, spectral detection range from 268-2017cm-1). After spectral processing a bacterial database was created using planktonic bacteria. Predictions of species in a biofilm and mapping was performed using multivariate statistical analysis.

Results: The Raman spectra show a specific fingerprint region (600-1800 cm-1) where differentiation between different strains are apparent. Using multivariate statistical methods it is possible to differentiate the strains of interest. In combination with structural spectral analysis, it is possible to predict species in artificially grown biofilms. Two-dimensional mapping allowed the visualization of the distribution based on their location of the acquired spectra in a specified random window.

Conclusion: Confocal Raman microscopy was able to differentiate clusters of oral bacteria in a subgingival biofilm model. This preliminary analysis is showing the potential of this technology in biofilm assessment and bacterial differentiation and may be used as an alternative to confocal laser scanning microscopy in the future. In addition, the developed methodology has the potential to be applied to different multi-species biofilms beyond the scope of oral biofilms.
Application of hollow fibre membrane reactor for biological removal of H2S
Authors: Das Jewel , Ravishankar Harish , Lens Piet
Published: July 2020

Hydrogen sulfide (H2S) is a toxic pollutant and harmful to human health. Industries such as pulp and paper manufacturing, rayon production, natural gas extraction and refining, and crude petroleum refineries generate waste gas streams with high H2S concentrations. Both physico-chemical and biological methods are used for H2S removal from the gas stream. Biological methods offer several advantages such as environmental friendly, less expensive and require simple operation and maintenance compared to physico-chemical methods. In this study, a hydrophilic hollow fibre membrane (HFM) based bioreactor configuration has been tested for biological H2S removal. Three reactors were fabricated and operated for ~ 3 months where two reactors were used for biological conversion process and the third reactor was used for abiotic process. The effective membrane area of a HFM module used in each reactor was 0.0138 m2. The bioreactors demonstrated efficient gas-liquid mass transfer through the HFM module and achieved ~ 99% removal efficiency with an elimination capacity of ~ 17.0 g m-3 h-1. The H2S flux of the bioreactor was ~ 0.20 g m-2 day-1 which was ~ 9 times higher than the abiotic reactor for an inlet H2S concentration of ~ 0.90 g m-3. The overall mass transfer coefficient value for the biotic process was 17.2 µm s-1 which was ~ 25 times higher than the abiotic process. The bioreactors demonstrated both microbial attached growth on the membrane surface and suspended growth in the liquid phase. Microbial community analysis confirmed the presence of diverse sulfur-oxidizing bacteria at genus level including Acinetobacter, Dechloromonas, Hydrogenophaga, Rhodopseudomonas and Sulfurospirillum. Moreover, the enrichment of other bacterial genera such as ammonia-oxidizing (e.g. Nitrosospira), organic matter degrading (e.g. Trichococcus) and methanogenic (e.g. Methanosaeta) microorganisms demonstrate the diverse microbial ecology of the sludge growing in the bioreactor.
Enhanced erosion resistance of biopolymer-enriched B. subtilis NCIB 3610 biofilms
Authors: Hayta Elif Nur , Lieleg Oliver
Published: July 2020

Erosion resistance is one of the advantages bacteria gain by producing biofilms. While it is undesirable for us humans when biofilms grow on medical devices or industrial pipelines, biofilms with a high erosion resistance can be advantageous for biotechnological applications. Here, we demonstrate how the erosion resistance of B. subtilis NCIB 3610 biofilms can be enhanced by integrating foreign (bio)polymers such as γ-polyglutamate (PGA), alginate and polyethylene glycol (PEG) into the matrix during biofilm growth.

Artificial enrichment of the NCIB 3610 biofilms with these biopolymers causes a significant increase in the erosion resistance by slightly changing the surface topography: A decreased cavity depth on the surface results in an alteration in the mode of surface superhydrophobicity, and we obtain a state that is located somewhere between rose-petal like and lotus-like wetting resistance. Surprisingly, the viscoelastic and microscopic penetration properties of the biofilms are not affected by the artificial incorporation of (bio)polymers. As we obtained similar results with all the biopolymers tested (which differ in terms of charge and molecular weight), this indicates that a variety of different (bio)polymers can be employed for a similar purpose.

The method introduced here may present a promising strategy for engineering beneficial biofilms such, that they become more stable towards shear forces caused by flowing water but, at the same time, remain permeable to nutrients or other molecules.
Interaction of flow field and biofilm formation in a dripper supplied by reclaimed wastewater
Authors: Ait Mouheb Nassim , Qian Jueying , Wagner Michael , Horn Harald
Published: July 2020

In the reclaimed wastewater reuse using drip irrigation, one of the main issues is the bio-clogging of drippers and decrease of water distribution efficiency in field level. However, the relation between the complex flow created along the dripper (in general formed by a milli-channel with labyrinth geometry) and the biofouling development are rarely studied.

In order to improve the knowledge of these mechanisms, the objective was to combine the numerical flow simulations to three-dimensional measurements of biofilm along a milli-fluidic system (nominal flow rate 1L/h) fed by treated wastewater. At first, using the Optical Coherence Tomography (OCT) method and based to Qian et al, 2018 studies, the bio-clogging structure was measured at different levels of fouling (up to 77% of channel volume). Secondly, the new fouled dripper geometries were integrated to 3D CFD models (using comsol multiphysics software) to analyse the effect of biofilm on flow topology and the dripper hydraulic parameters (pressure drop, shear stress, turbulence kinetic energy in particular).

The results show that the main areas of biofilm growth correspond to vortices zones where fluid velocity, turbulent kinetic energy values and shear stress are lowest. When the level of clogging increases, the numerical plot of stream lines show local perturbation and reduction of vortices areas caused by their interactions with the biofilm structure. There is also a gradual increase in pressure drop along the milli-channel comparing to initial clean dripper. Finally, by characterising the flowrate in function of inlet pressure and according to Karmeli, 1977, the increase of biofilm formation induces also a modification of the global flow regime in the dripper, i.e. the transfer from a turbulent to a laminar regime.

Qian, J., Horn, H., Tarchitzky, J., Chen, Y., Katz, S., Wagner, M., (2017). Water quality and daily temperature cycle affect biofilm formation in drip irrigation devices revealed by optical coherence tomography. Biofouling 33, 211–221. 
Karmeli, D. (1977). Classification and flow regime analysis of drippers. J Agric Eng Res 22:165–173
Can rhamnose-based glycolipids nanoparticles be an alternative to fight biofilms on medical devices?
Authors: Tomé Carolina , Anjos Inês , Martin Victor , Santos Catarina , Gonçalves Lidia , Fernades Maria H , Bettencourt Ana F. , Gomes Pedro , Ribeiro Isabel A.C.
Published: July 2020

Biofilm development on medical devices is of particular concern and finding new strategies for preventing surface colonization and infection development are urgent. Antimicrobial biosurfactants such as rhamnolipids (RLs), emerge as one possible solution due their lack of resistance development. Using nanoparticles as delivery systems for these compounds may be a promising alternative in the context of biofilm-infections control. As such, the aim of this study was to encapsulate RLs into chitosan nanoparticles (RLs-NPs), test their antimicrobial activity and their biocompatibility profile.

Blank nanoparticles (b-NPs) and RLs-NPs were prepared by ionic gelation. For particles characterization, zeta potential, size distribution and encapsulation efficiency were performed. Minimal inhibitory concentration and biofilm inhibition ability were evaluated towards Staphylococcus aureus (ATCC 25923). To access NPs cytocompatibility the in vitro tetrazolium dye assay (MTT) and morphology observation were performed with a mouse fibroblastic cell line (L929).

RLs-NPs presented an encapsulation efficiency of 74.2±1.3%, a size ranging from 300 to 400 nm and a zeta potential of  37±1 mV. The minimum inhibitory concentration of RLs-NPs was 130 mg/mL and a 99% biofilm inhibition was achieved with these NPs meaning that their antimicrobial activity is also effective towards sessile bacteria. When compared to control, cell cultures grown in the presence of RLs-NPs presented no significant differences regarding the MTT reduction values and morphology analysis, suggesting that NPs up to 500 mg/mL did not significantly interfere with viability and proliferation.

The results revealed that the RLs-NPs were able to inhibit bacterial growth showing adequate cytocompatibility and might become, after additional studies, a possible approach to fight S. aureus biofilm associated infections.

Acknowledgments: Support for this work was provided by FCT through Portuguese government, PTDC/BTM-SAL/29335/2017 and Pest-UID/DTP/04138/2019
Using a composite flow law to model deformation in the NEEM deep ice core, Greenland – Part 2: The role of grain size and premelting on ice deformation at high homologous temperature
Authors: Kuiper Ernst-Jan N. , de Bresser Johannes H. P. , Drury Martyn R. , Eichler Jan , Pennock Gill M. , Weikusat Ilka
Published: July 2020

Abstract. The ice microstructure in the lower part of the North
Greenland Eemian Ice Drilling (NEEM) ice core consists of relatively fine-grained ice with a single maximum crystallographic preferred orientation
(CPO) alternated by much coarser-grained ice with a partial (great circle)
girdle or multi-maxima CPO. In this study, the grain-size-sensitive (GSS)
composite flow law of Goldsby and Kohlstedt (2001) was used to study the
effects of grain size and premelting (liquid-like layer along the grain
boundaries) on strain rate in the lower part of the NEEM ice core. The
results show that the strain rates predicted in the fine-grained layers are
about an order of magnitude higher than in the much coarser-grained layers.
The dominant deformation mechanisms, based on the flow relation of Goldsby
and Kohlstedt (2001), between the layers is also different, with basal slip
rate limited by grain boundary sliding (GBS-limited creep) being the
dominant deformation mechanism in the finer-grained layers, while
GBS-limited creep and dislocation creep (basal slip rate limited by
non-basal slip) contribute both roughly equally to bulk strain in the coarse-grained layers. Due to the large difference in microstructure between finer-grained ice and the coarse-grained ice at premelting temperatures
(T>262 K), it is expected that the fine-grained layers deform at
high strain rates, while the coarse-grained layers are relatively stagnant.
The difference in microstructure, and consequently in viscosity, between
impurity-rich and low-impurity ice can have important consequences for ice
dynamics close to the bedrock.
Impact of Financial Market Uncertainty on Market Returns: A Global Analysis
Authors: Abid Maryam , Siddique Danish Ahmed
Published: July 2020

This paper examines the effect of financial market uncertainty on market returns of different countries of the world. The effect of other macroeconomic like Consumer Price Index (CPI), Real Interest Rates (R.IR), Market Capitalization (MCAP), and Gross Domestic Product per capita growth (GDPPCG).For analyzing this relationship, around 40 countries data including developed and developing countries, over the period of 10 years from 2009-2018. For analysis, Panel Least Square (PLS) was used. Fixed Effect Model (FEM) is used to check the overall strength of the model. Group correlation was also performed on overall variables to check the causal relationship between all the variables and individual regression tests are also conducted country wise to explore that how much this model is applicable, descriptive analysis for market return and uncertainty to check the moments of these variables. The overall results it is concluded that market returns are affected by the financial markets uncertainty in the long run and it is a significant variable in explaining market returns while overall test results proved a positive relationship with market returns but individual testing of this model on each country shows, more than half countries in the study have a negative relationship of financial market uncertainty with market returns. Along this, other macro-economic variables impact is also measured over market returns of the world which shows all variables Consumer Price Index, Real Interest Rates and Market Capitalization except Gross Domestic Product per capita growth have a negative relationship with the Equity Market returns.
REPRINTED WITH PERMISSION OF IASP – PAIN 160 (2019) 2086–2092: Opioid use, pain intensity, age, and sleep architecture in patients with fibromyalgia and insomnia
Authors: Curtis Ashley F. , Miller Mary Beth , Rathlnakumar Himangshu , Robinson Michael , Staud Roland , Berry Richard B. , McCrae Christina S.
Published: July 2020

Opioid use and sleep disruption are prevalent in fibromyalgia. Yet, the effects of opioids on physiological sleep in fibromyalgia are unclear. This study assessed associations between opioid use/dosage and polysomnographically assessed sleep in patients with fibromyalgia and insomnia (FMI) and examined moderating effects of age and pain. Participants (N = 193, Mage 551.7, SD = 11.8, range = 18–77) with FMI completed ambulatory polysomnography and 14 daily diaries. Multiple regression determined whether commonly prescribed oral opioid use or dosage (among users) independently predicted or interacted with age/pain intensity to predict sleep, controlling for sleep medication use and apnea hypopnea index. Opioid use predicted greater %stage 2 and lower% slow-wave sleep (%SWS). Opioid use interacted with age to predict greater sleep onset latency (SOL) in middle-aged/older adults. Among opioid users (n = 65, ~3 years usage), opioid dose (measured in lowest recommended dosage) interacted with age to predict SOL and sleep efficiency; specifically, higher dosage predicted longer SOL and lower sleep efficiency for older, but not middle-aged/younger adults. Opioid dose interacted with pain to predict %SWS and arousal index. Specifically, higher dosage predicted reduced %SWS and higher arousal index for individuals with lower pain, increased %SWS for individuals with higher pain, and did not predict%SWS for patients with average pain. Opioid use/dosage did not predict wake after sleep onset, total sleep time, %stage 1 or %rapid eye movement sleep. Opioid use prompts changes in sleep architecture among individuals with FMI, increasing lighter sleep and reducing SWS. Sleep disruption is exacerbated at higher opioid doses in older adults and patients with low pain.
Study on extraction of pollutant free
flammable fuel from contaminated
automobile waste lube oil
Authors: Thanikachalam J. , Karthikeyan S.
Published: July 2020

Purpose: of this paper is to investigate the reusability of contaminated waste lubricant oil
as flammable fuel by thermal and catalytic cracking process followed by distillation. It also
includes the study of using Zeolite and Nickel nano particles as catalyst and its influence
catalytic cracking.
Design/methodology/approach: A conventional sterilization technique called Autoclaving
method, uses high-pressure steam to separate water and other solid waste from the lube oil.
It is followed by thermal cracking which breaks the molecular chains and decompose the
waste lube oil. The autoclaving process works by the concept that the boiling point of water
(or steam) increases when it is under pressure.
Findings: Now a days, Industrial and Automobile waste lubricating oils are giving big threat
ecology while burning and disposing on bare land. Furthermore, they discharged into the
open environment which might make destructive sicknesses to ecology. In water, oil is a
visible pollutant, floating as a scum on the surface. Moreover, there is a gradual rise in fuel
requirement across the globe, and the consumption of oil assets have driven the researchers
to find elective power for internal combustion engines. By the way, diminishing of fossil
sources, growing of demand and cost of petroleum based fuels and its environmental
hazards as a result of burning or disposing on land have encouraged to investigate
possibility of recycling of waste engine oil.
Research limitations/implications: A series of process such as filtration, cracking
followed by distillation needs expensive experimental setup and regular maintenance as the
extracted flammable oil fuel possess significant range of dynamic viscosity values. As all real
fluids has its own viscosity, in near future, an investigation is about to do on its behaviour on
blending with other flammable fluids.
Practical implications: Although the result of this investigation conforming its flammable
characteristic of the extracted fuel, the quantity of pollutant free flammable fuel from waste
contaminated lube oil being extracted is significant, the cost of catalyst is considerably
more, as it plays the most vital part in cracking. This effort likely also reduces foreign
exchange, reduces greenhouse emissions and enhances regional development especially
in developing countries.
Originality/value: The novelty of the work is to prepare pollutant free flammable fuel from
waste Lube oil by catalytic cracking process. Here Zoelite and Nickel nanoparticles are used as catalyst which breaks the long-chain molecules of the high boiling hydrocarbon liquids into much shorter molecules.
Estimation of the depth of penetration
in a plunging hollow jet using artificial
intelligence techniques
Authors: Bodana D. , Tiwari N.K. , Ranjan S. , Ghanekar U.
Published: July 2020

Purpose: Experimental investigations assessment and comparison of different classical
models and machine learning models employed with Gaussian process regression (GPR)
and artificial neural network (ANN) in the estimation of the depth of penetration (Hp) of
plunging hollow jets.
Design/methodology/approach: In this analysis, a set of data of 72 observations is
derived from laboratory tests of plunging hollow jets which impinges into the water pool
of tank. The jets parameters like jet length, discharge per unit water depth and volumetric
oxygen transfer coefficient (Kla20) are varied corresponding to the depth of penetration
(Hp) are estimated. The digital image processing techniques is used to estimate the depth
of penetration. The Multiple nonlinear regression is used to establish an empirical relation
representing the depth of penetration in terms of jet parameters of the plunging hollow
jets which is further compared with the classical equations used in the previous research.
The efficiency of MNLR and classical models is compared with the machine learning
models (ANN and GPR). Models generated from the training data set (48 observations) are
validated on the testing data set (24 observations) for the efficiency comparison. Sensitivity
assessment is carried out to evaluate the impact of jet variables on the depth of penetration
of the plunging hollow jet.
Findings: The experimental performance of machine learning models is far better than
classical models however, MNLR for predicting the depth of penetration of the hollow jets.
Jet length is the most influential jet variable which affects the Hp.
Research limitations/implications: The outcomes of the models efficiency are based
on actual laboratory conditions and the evaluation capability of the regression models may
vary beyond the availability of the existing data range.
Practical implications: The depth of penetration of plunging hollow jets can be used in
the industries as well as in environmental situations like pouring and filling containers with
liquids (e.g. molten glass, molten plastics, molten metals, paints etc.), chemical and floatation
process, wastewater treatment processes and gas absorption in gas liquid reactors.
Originality/value: The comprehensive analyses of the depth of penetration through the
plunging hollow jet using machine learning and classical models is carried out in this study.
In past research, researchers were used the predictive modelling techniques to simulate the
depth of penetration for the plunging solid jets only whereas this research simulate the depth
of penetration for the plunging hollow jets with different jet variables.
SOCIAL RIGHTS OF THE POLES IN THE UNITED KINGDOM AFTER BREXIT
Authors: Kaleta Paweł
Published: July 2020

Withdrawal of the United Kingdom of Great Britain and Northern Ireland from the European Union (Brexit) has definitely been bringing various consequences in the field of social security. It is therefore worthwhile to analyse it from the point of view of the social rights of Poles residing in the United Kingdom (as well as, in a comparative and auxiliary manner, of the British residing in Poland), following the formal conclusion of the withdrawal. The article therefore synthetically presents this current, post-Brexit situation, taking into account the ongoing transition period as well as the perspective of negotiations on the possible agreement(s) on future EU-UK relations. Notably, the rights in question have been preserved in the transition period, but their status afterwards remains open.
Prediction of bearing capacity
of H shaped skirted footings
on sand using soft computing techniques
Authors: Gnananandarao T. , Khatri V.N. , Dutta R.K.
Published: July 2020

Purpose: The present study aims to apply soft computing techniques, Artificial Neural
Network (ANN) and M5P model tree, to predict the ultimate bearing capacity of the H plan
shaped skirted footing on the sand
Design/methodology/approach: A total of 162 laboratory test data for the regular
plan shaped (square, circular, rectangular, and strip (up to L/B = 2.5) skirted footing were
collected from the literature to develop the soft computing-based models. These models
were later modified for the H Plan shaped skirted footing with the introduction of the
multiplication factor. The input variables chosen for the regular plan shaped footings were
skirt depth to width of the footing ratio (Ds/B), friction angle of the sand (􀉭), the ratio of the
interface friction angle-to-friction angle of sand (δ/􀉭), and length-to-width (L/B) ratio of the
footing. The output is the bearing capacity ratio (BCR, a ratio of the bearing capacity of the
skirted footing to the bearing capacity of un-skirted footing).
Findings: Sensitivity analysis was carried out to see the impact of the individual variable
on the BCR). The sensitivity results reveal that the skirt depth to width of the footing ratio
is the primary variable affecting the BCR. Finally, the performance of the developed soft
computing models was assessed using six statistical parameters. The results from the
statistical parameters reveal that model developed using ANN was performing superior to
the one prepared using M5P model tree technique for the prediction of the ultimate bearing
capacity of H plan shaped skirted footing on sand.
Research limitations/implications: The model equations are developed with
experimental laboratory data. Hence, these equations need further improvement by using
field data. However, until now there no field data have been available to include in the
present data set.
Practical implications: These proposed model equations can be used to predict the
bearing capacity of the H-shaped footing with the help of Ds/B, 􀉭, δ/􀉭 and L/B without
performing the laboratory experiments.
Originality/value: There is no such model equation that was developed so far for the
H-shaped skirted footings. Hence, an attempt was made in this article to predict the bearing
capacity of the H-shaped footing by using available experimental data with the help of soft
computing techniques.
ESTABLISHING HEALTHY AND ACTIVE AGEING POLICIES IN POLAND, THE CZECH REPUBLIC AND BULGARIA
Authors: Sowa-Kofta Agnieszka
Published: July 2020

Central and Eastern European populations are entering a period of rapid aging. Older people are experiencing numerous problems associated with deteriorating health and functional limitations, creating pressure for adequate response from the state’s health and social policy. The article is based on information collected in the two international projects: CEQUA LTC Network and Pro-Health 65+ and its goal is to review policies on healthy and active aging formulated in recent decades in three countries: Czech Republic, Bulgaria and Poland. The health promotion programs in these countries are aimed at improving the health and well-being of the population, referring to the concept of healthy aging in relation to health risks, prevention of chronic diseases and disability in old age. At the same time, in the social sector, strategies and programs were brought to life referring to the concept of active aging, underlying the need for participation of older people in social life, creation of an elderly friendly environment and development of services supporting older people. Implementation of these policies and programmes is affected by limited financial resources, low awareness of the problems of the older population in local communities, and lack of local resources to create the appropriate infrastructure. The effectiveness of programs’ implementation is also influenced by the sectoral nature of programmes and poor intersectoral cooperation.
REMUNERATION AND MOTIVATION OF EMPLOYEES AS AN IMPORTANT ELEMENT OF COMPANY MANAGEMENT. JOB CRAFTING – A NEW METHOD FOR BUILDING ENGAGEMENT
AND SENSE OF A WORK SENSOR
Authors: Lopata Ewelina
Published: July 2020

The changing socio-economic situation means that companies must create new solutions in the field of human resource management, while remembering about the diversity of employees. Nowadays, companies wanting to achieve market success and maximize profits must take into account many factors, both internal and external. Undoubtedly, the most valuable asset of any organization is human capital, which is why it is so important to implement the correct actions that combine the interests of the employee and the employer. The main purpose of this article is to present the issue of remuneration and motivating employees as an important element affecting the enterprise management process. Particular attention has been devoted to the role played by the above instruments in the employee management process. The study focuses on discussing the above spheres, because both areas condition the creation of organizational development concepts and affect the formation of long-term development plans. The article attempts to answer two hypotheses contained in the introduction. The last part of the study describes a new method of building employees’ commitment and sense of the sense of work which is job crafting.
Educação Financeira em Livros Didáticos de Matemática dos Anos Finais do Ensino Fundamental: Análise de uma Coleção
Authors: Azevedo Suedy Santos de , Pessoa Cristiane
Published: July 2020

Neste artigo, recorte de uma dissertação de Mestrado, apresentamos uma discussão sobre Educação Financeira (EF), bem como os resultados encontrados na análise de uma coleção de livros didáticos de Educação Matemática Crítica (EMC), especificamente os Ambientes de Aprendizagem, proposta por Skovsmose (2014). Analisamos as atividades de EF encontradas nos livros e o manual do professor, a fim de observar as orientações fornecidas para as atividades. Encontramos 54 atividades nos livros de 6o , 7o , 8o e 9o anos e a maior parte das atividades foi categorizada como Ambiente de aprendizagem do tipo 3 (semirrealidade/exercício). O manual do professor, de maneira geral, pouco contribui na orientação de possibilidades de trabalho das atividades. Consideramos importante a inserção da EF em livros didáticos de Matemática, embora a temática ainda não seja obrigatória no espaço escolar.
MicroRNA Prediction in the FVIII Gene Locus: A Step Towards Hemophilia A Control
Authors: Rezaei Halimeh , Motovali-Bashi Majid , Khalilian Sheyda
Published: July 2020

Background: Various mutations in factor VIII (F8) gene locus are led to an X-linked bleeding disorder in patients with hemophilia A. One of the leading causes of inefficient treatment available for hemophilia A is the lack of specific and sensitive diagnostic procedure for the disease. The discovery of a functional role of microRNAs (miRNAs) in the pathogenesis of a wide range of human diseases makes them the potential, non-invasive, biomarker candidates for hemophilia A. Therefore, advances in computational tools for miRNA discovery leads to numerous recent publications on miRNAs as putative biomarkers. Objectives: The current study aimed at scanning the F8 gene region to predict novel miRNAs as regulators of the F8 gene. Methods: The potential of the FVIII locus to express new miRNAs was studied via reliable bioinformatics databases, such as SSCprofiler, RNAfold, miREval, miR-Find, FOMmiR, UCSC genome browser, and miRBase. Results: Data analysis from previously mentioned databases offered two stem-loop structures predicted to express novel miRNAs. Conclusions: The presented stem-loop structures can be used as powerful non-invasive biomarkers in early diagnosis of the disease and regulation of the factor VIII gene after subsequent experimental verification.
Learning from What Color Experiences Are Good For
Authors: Jackson Frank ,   The Harvard Review of Philosophy
Published: July 2020

Color is an incredibly controversial topic. Here is a sample of views taken seriously: colors are dispositions to look coloured; colors are physical properties of surfaces or of light; colors are properties of certain mental states, which get projected onto the surfaces of objects or onto reflected or transmitted light; colors are an illusion; colors are sui generis. One hopes to break the impasse by finding a compelling starting point—one drawing on obvious points that are common ground—which naturally evolves into the theory of color one likes. I start with remarks about the utility of having mental states with a phenomenology, remarks which are, I urge, non-controversial. I develop them into the theory of color I favor. According to it, colors are properties of objects as objective as their shapes. The final section explains how the theory handles the best argument for subjectivism about color.
Revision of the stygobiont gastropod genera Plagigeyeria Tomlin, 1930 and Travunijana Grego & Glöer, 2019 (Mollusca; Gastropoda; Moitessieriidae and Hydrobiidae) in Hercegovina and adjacent regions
Authors: GREGO Jozef
Published: July 2020

The genus Plagigeyeria Tomlin, 1930 is one of the most typical elements representing the stygobiont fauna in the southern Dinaric Alps. In the current study I present the territory of Hercegovina (and its adjacent regions of Bjelašnica and the Dalmatian coast containing transboundary aquifers) as one of the two main biodiversity hotspots for distribution of the genus. It is comparable with the species radiation of Plagigeyeria in the Kotor Bay–Skadar Lake Basin area. My study of the karst springs and caves revealed, besides the presently known species, twelve new Plagigeyeria taxa detected in so-far uninvestigated karstic aquifers: Plagigeyeria erossi sp. nov., P. ljutaensis sp. nov., P. konjicensis sp. nov., P. pseudocostellina sp. nov., P. reischuetzorum sp. nov., P. olsavskyi sp. nov., P. listicaensis sp. nov., P. ozimeci sp. nov., P. jakabi sp. nov., P. angyaldorkae sp. nov., P. vriosticaensis sp. nov. and P. lewarnei sp. nov. Closer shell morphology investigation supported by the protoconch morphology revealed a presence of another genus within the former Plagigeyeria complex. The following taxa are transferred herein to Travunijana Glöer & Grego, 2019: Plagigeyeria robusta Schütt, 1959, P. robusta asculpta Schütt, 1972, P. ovalis Kuščer, 1933, P. edlaueri Schütt, 1961, P. klemmi Schütt, 1961, P. nitida Schütt, 1963, P. angelovi Schütt, 1972 and P. tribunicae Schütt, 1963, plus a new species, Travunijana gloeri sp. nov., is described for the genus. Distribution maps of both genera, Plagigeyeria and Travunijana, over the karst aquifers of Hercegovina and adjacent regions are presented with respect to the hydrogeological separation of the known spring karst conduits and aquifers.
Un modèle d’accompagnement du développement pédagogique et organisationnel pour soutenir la mise en oeuvre d’un modèle de réponse à l’intervention
Authors: Guay Marie-Hélène , Gagnon Brigitte
Published: July 2020

Dans le présent article, nous présentons un modèle d’accompagnement du développement pédagogique et organisationnel pour soutenir la mise en oeuvre d’un modèle de la réponse à l’intervention (RàI). Ce cadre a été utilisé dans le déploiement des ressources pour appuyer l’apprentissage du langage oral et écrit au préscolaire/premier cycle du primaire dans deux commissions scolaires au Québec. Ses origines, sa nature, ses finalités et des actions fondamentales pour le mettre en oeuvre sont détaillées. Enfin, des pistes de réflexion sont proposées à l’intention des gestionnaires en éducation pour guider leurs décisions et leurs actions.
Un modèle de réponse à l’intervention (RàI) comportementale : le soutien au comportement positif (SCP)
Authors: Bissonnette Steve , Bouchard Carl , St-Georges Normand , Gauthier Clermont , Bocquillon Marie
Published: July 2020

De nombreux systèmes éducatifs ont amorcé, au cours des dernières années, un virage important vers une gestion axée sur les résultats (Bourgault, 2004). Or, ce type de gestion nous amène à poser un regard sur la réussite des élèves ayant des difficultés comportementales, car ce sont eux les plus susceptibles d’abandonner l’école (MELS, 2006). Par conséquent, il devient essentiel d’implanter des systèmes d’intervention, fondés sur des données probantes, favorisant la prévention de ces difficultés. Le systèmePositive Behavioural Interventions and Supports(PBIS) est fondé sur des données probantes (Lapointe et Freiberg, 2006). Le PBIS, appelé en français le soutien au comportement positif (SCP), représente un modèle de réponse à l’intervention comportementale. Dans cet article, nous décrivons le SCP. Par la suite, nous montrons ses effets sur la diminution des écarts de conduite majeurs des élèves à l’intérieur d’écoles québécoises contribuant ainsi à la prévention des difficultés comportementales.
'Social media' ante el discurso del odio
Authors: Martínez Martínez Silvia
Published: July 2020

En pleno confinamiento y contexto de pandemia, las plataformas sociales han vuelto a protagonizar un profundo debate en torno a su actuación ante la difusión del discurso del odio que se puede producir en estos espacios de comunicación. Un debate en el que actores políticos y económicos se han ido pronunciando junto a los propios usuarios y agentes relacionados con las empresas tecnológicas. La discusión se ha visto marcada por argumentos que han enarbolado la defensa de la libertad de expresión y la limitación de la censura, frente a otros que abogan por la necesidad de intervenir para frenar los mensajes de odio.
Resignificaciones sociales del silencio y socialidad de la escucha en Ciudad de México. Memoria, historia y sentidos en el México contemporáneo
Authors: Bieletto Bueno Natalia
Published: July 2020

En este texto se problematiza la noción de “silencio” y sus usos metafóricos para asistir la movilización de afectos entre los habitantes de Ciudad de México. El argumento toma como premisa que la escucha es una experiencia integral (corporal, cognitiva, y senso-afectiva) y una forma de “inscripción en la consciencia y la memoria” (Rivas, 2019; Gallagher, 2016). Seguidamente, se formulan diversas reflexiones al respecto de cómo momentos coyunturales en la historia reciente de Ciudad de México pueden estar moldeando las formas de escuchar, así como de percibir y significar el silencio entre los habitantes de la ciudad capital. Esta referencia a momentos coyunturales implica la consideración de instancias de traumas colectivos, sean estos por causas sociales o naturales, que acaban por ligarse a la memoria colectiva y la historia local de la Ciudad de México. En particular, se describen las reacciones socio-afectivas al terremoto que tuvo lugar en 2017; y su relación senso-perceptual con los seísmos del año 1985 y con dos trágicas masacres estudiantiles ocurridas en 1968 y más recientemente en 2014. Los eventos aludidos han sido de una magnitud afectiva tal que han requerido de un reacomodo sensorial para nombrar lo vivido y, sobre todo, para poder dar sentido a lo perdido, a lo ausente, a lo desaparecido. Estas formas de nombrar –o mejor dicho de no-nombrar– las ausencias, pero sí de performar el dolor que generan, permiten hablar de una reformulación de los significados en torno al referente “silencio”. La propuesta consiste en explorar formas performáticas de la cultura, suponiendo que las modalidades de escucha e interpretación de la díada escucha/silencio en los distintos momentos históricos aludidos permiten conocer los usos afectivos del silencio, la performatividad de la escucha y la función de ambos en el procesamiento colectivo del trauma.