bluuebunny/crossref_metadata_2025 huggingface dataset:
Early Retinal Changes by OCT Angiography and Multifocal Electroretinography in Diabetes
Authors: Frizziero Luisa , Midena Giulia , Longhin Evelyn , Berton Marianna , Torresin Tommaso , Parrozzani Raffaele , Pilotto Elisabetta
Published: October 2020

Background: To evaluate the earliest retinal morphological and functional changes in diabetic eyes without or with early signs of diabetic retinopathy (DR). Methods: Twenty-two eyes with no DR (noDR group), 22 eyes with mild DR (DR group), and 18 healthy nondiabetic eyes (controls) were enrolled. All eyes were studied by means of spectral domain optical coherence tomography (OCT), OCT angiography (OCTA), and multifocal electroretinogram (mfERG). Results: A significantly higher number of OCT hyperreflective intraretinal foci (HRF) was found in both noDR and DR groups versus controls, but not between DR groups. The OCTA parameters of the superficial vascular plexus (SVP) were significantly reduced in the noDR group both versus controls and DR group (p < 0.05). The OCTA parameters of the intermediate capillary plexus (ICP) were significantly reduced in the DR group versus controls. An increased number of altered hexagons on mfERG was found in the noDR versus the DR group (p = 0.0192). Conclusions: Retinal vascular and functional parameters are differently involved in diabetic eyes; major vascular changes in the SVP and functional alterations of the mfERG are present in diabetic eyes with no clinical microvascular signs of DR, while ICP is mainly involved when early ophthalmoscopic signs of DR are present. The integrated use of mfERG and OCTA provides new significant insights into the pathogenesis of diabetic related retinal disease.
Short-Term Clinical Outcomes of Single Versus Dual Antiplatelet Therapy after Infrainguinal Endovascular Treatment for Peripheral Arterial Disease
Authors: Ipema Jetty , Welling Rutger H. A. , Bakker Olaf J. , Bokkers Reinoud P. H. , de Vries Jean-Paul P. M. , Ünlü Çagdas
Published: October 2020

After infrainguinal endovascular treatment for peripheral arterial disease (PAD), it is uncertain whether single antiplatelet therapy (SAPT) or dual antiplatelet therapy (DAPT) should be preferred. This study investigated major adverse limb events (MALE) and major adverse cardiovascular events (MACE) between patients receiving SAPT and DAPT. Patient data from three centers in the Netherlands were retrospectively collected and analyzed. All patients treated for PAD by endovascular revascularization of the superficial femoral, popliteal, or below-the-knee (BTK) arteries and who were prescribed acetylsalicylic acid or clopidogrel, were included. End points were 1-, 3-, and 12-month MALE and MACE, and bleeding complications. In total, 237 patients (258 limbs treated) were included, with 149 patients receiving SAPT (63%) and 88 DAPT (37%). No significant differences were found after univariate and multivariate analyses between SAPT and DAPT on 1-, 3-, and 12-month MALE and MACE, or bleeding outcomes. Subgroup analyses of patients with BTK treatment showed a significantly lower 12-month MALE rate when treated with DAPT (hazard ratio 0.33; 95% confidence interval 0.12–0.95; p = 0.04). In conclusion, although patient numbers were small, no differences were found between SAPT and DAPT regarding MALE, MACE, or bleeding complications. DAPT should, however, be considered over SAPT for the subgroup of patients with below-the-knee endovascular treatment.
Experimental Observations on Impact Velocity and Entrapped Air for Standing Wave Impacts on Vertical Hydraulic Structures with Overhangs
Authors: de Almeida Ermano , Hofland Bas
Published: October 2020

This study focusses on increasing the understanding on vertical hydraulic structures with relatively short overhangs subjected to standing wave impacts. To this end, the impact velocity and the entrapped air are studied in detail, given their influence on the impulsive loading characteristics and consequently on the structural dynamic response. This study is based on regular wave laboratory experimental data obtained for relatively short overhangs with respect to the wave length and with respect to the overhang height. The laboratory tests illustrate the complex wave hydrodynamics before the wave impacts, influenced by the incident wave conditions and structural characteristics. Regarding the impact velocity, the experimental measurements with a wall wave gauge in the tests without overhangs show that the maximum upward velocities deviate from linear wave theory between +5.5% and +13.0%, while the zero-crossing upward velocities deviate from linear wave theory between +1.9% and +7.0%. The zero-crossing upward velocities estimated from third order wave theory deviate from the linear wave theory between +1.8% and +4.7%. In the tests with overhangs, the maximum upward velocity below the overhang estimated by camera recording measurements deviates from linear wave theory between −11.8% and +13.4%. It was also found that when considering the experimental impact velocity from camera recordings in the tests with overhangs, the mean effective bounce-back factor β deviates relatively little from when linear wave theory is used (≈1%), while the uncertainty described by the standard deviation increases significantly (≈35%). Regarding the entrapped air, it is shown that the interaction between incident wave parameters and structural configurations leads to a large variation in the entrapped air area, up to a factor of 5.7 for shorter overhangs and a factor of 9.5 for longer overhangs. This variability in entrapped air characteristics leads to significant effects on the loading on the structure, as observed by the variability on pressure measurements. The experimental results showed increasing impact durations and increasing effective bounce-back factor β in the tests with increasing entrapped air dimensions. This study highlights the importance of the details of the impact velocity and entrapped air for load estimations during the design of vertical hydraulic structures exposed to standing wave impacts. This is particularly important for thin structures such as steel gates which are susceptible to a dynamic behaviour under such impulsive loads.
The Effect of the Second-Order Wave Loads on Drift Motion of a Semi-Submersible Floating Offshore Wind Turbine
Authors: Pham Thanh-Dam , Shin Hyunkyoung
Published: October 2020

Floating offshore wind turbines (FOWTs) have been installed in Europe and Japan with relatively modern technology. The installation of floating wind farms in deep water is recommended because the wind speed is stronger and more stable. The design of the FOWT must ensure it is able to withstand complex environmental conditions including wind, wave, current, and performance of the wind turbine. It needs simulation tools with fully integrated hydrodynamic-servo-elastic modeling capabilities for the floating offshore wind turbines. Most of the numerical simulation approaches consider only first-order hydrodynamic loads; however, the second-order hydrodynamic loads have an effect on a floating platform which is moored by a catenary mooring system. At the difference-frequencies of the incident wave components, the drift motion of a FOWT system is able to have large oscillation around its natural frequency. This paper presents the effects of second-order wave loads to the drift motion of a semi-submersible type. This work also aimed to validate the hydrodynamic model of Ulsan University (UOU) in-house codes through numerical simulations and model tests. The NREL FAST code was used for the fully coupled simulation, and in-house codes of UOU generates hydrodynamic coefficients as the input for the FAST code. The model test was performed in the water tank of UOU.
An Integrated Biomarker Approach Using Flounder to Improve Chemical Risk Assessments in the Heavily Polluted Seine Estuary
Authors: Borcier Elodie , Charrier Grégory , Couteau Jérôme , Maillet Géraldine , Le Grand Fabienne , Bideau Antoine , Waeles Matthieu , Le Floch Stéphane , Amara Rachid , Pichereau Vianney , Laroche Jean
Published: October 2020

The objective of this study was to develop an integrative approach in ecotoxicology (from biomarkers to population genetics) to assess the ecological status of fish populations. Flounders (Platichthys flesus) collected after the spawning season in the heavily polluted Seine estuary were compared with the moderately polluted Bay of Douarnenez. The muscle energetic reserves were highly depleted in Seine vs. Douarnenez fish. The Seine fish displaying a reduced capacity to manage the oxidative stress and a higher energetic metabolism. An increase in the content of muscle membrane phospholipids (sphingomyelin, phosphatidylserine, free sterols) was detected in the Seine vs. Douarnenez fish. The data integration allowed to hypothesize relationships between membrane phospholipids, xenobiotic metabolism, bioenergetics, and antioxidant defence. The genetic diversity considering neutral markers was maintained in the heavily polluted Seine population compared with the Douarnenez population. Finally, we suggest that the high physiological cost of tolerance to toxicants in the Seine flounder population could compromise its capacity to respond in the future to an additional stressor like warming waters in shallow depth. Thus, this population could be submitted to an ecological risk.
Contribution of Multiplex Immunoassays to Rheumatoid Arthritis Management: From Biomarker Discovery to Personalized Medicine
Authors: Laborde Carlos M. , Castro-Santos Patricia , Díaz-Peña Roberto
Published: October 2020

Rheumatoid arthritis (RA) is a multifactorial, inflammatory and progressive autoimmune disease that affects approximately 1% of the population worldwide. RA primarily involves the joints and causes local inflammation and cartilage destruction. Immediate and effective therapies are crucial to control inflammation and prevent deterioration, functional disability and unfavourable progression in RA patients. Thus, early diagnosis is critical to prevent joint damage and physical disability, increasing the chance of achieving remission. A large number of biomarkers have been investigated in RA, although only a few have made it through the discovery and validation phases and reached the clinic. The single biomarker approach mostly used in clinical laboratories is not sufficiently accurate due to its low sensitivity and specificity. Multiplex immunoassays could provide a more complete picture of the disease and the pathways involved. In this review, we discuss the latest proposed protein biomarkers and the advantages of using protein panels for the clinical management of RA. Simultaneous analysis of multiple proteins could yield biomarker signatures of RA subtypes to enable patients to benefit from personalized medicine.
An Evaluation of Public Spaces with the Use of Direct and Remote Methods
Authors: Szczepańska Agnieszka , Pietrzyk Katarzyna
Published: October 2020

Public spaces play many important roles and constitute a vital component of the urban fabric, in particular in towns with historical centers. Effective management of public space should be based on the results of qualitative assessments. The quality of public space is usually evaluated directly during field surveys. However, field methods require considerable effort and time, which is why a remote sensing method based on satellite images and the Street View technology was proposed in this paper. Two Polish towns were evaluated, and the results generated by the direct and the remote approach were compared. The assessment focused on public spaces which constitute public property and promote direct human interactions. Both methods produced highly similar results, which indicates that remote sensing is a suitable technique for assessing the quality of public spaces.
Effects of Land Certification for Rural Farm Households in Ethiopia: Evidence from Gozamin District, Ethiopia
Authors: Gedefaw Abebaw Andarge , Atzberger Clement , Seher Walter , Agegnehu Sayeh Kassaw , Mansberger Reinfried
Published: October 2020

Economic theory notes tenure security is a critical factor in agricultural investment and productivity. Therefore, several African countries’ development initiatives enabled land titling to enhance tenure security. This paper examines the effect of land certification on tenure security, land investment, crop productivity and land dispute in Gozamin District, Ethiopia. In addition, the impact of land certification on farm households’ perceptions and confidence in land tenure and land use rights is investigated. Face-to-face interviews with 343 randomly selected farm households, group discussions and expert panels are the sources of primary data. Quantitative data are analyzed using various statistical tools and complemented by qualitative data. According to the results, most farm households (56%) feel that their land use rights are secure after the certification process. Only 17% fear that the government at any time could take their land use rights. The majority of farm households (71.7%) identified a reduction of disputes after certification and land management practices improved from 70.3% before certification to 90.1% after certification. As key factors for the increase of terracing and the application of manure, the study determined total farm size, the average distance from farm to homestead, perception of degradation, access to credit, training to land resource management, fear about land take-over by the government and total livestock holdings. Crop productivity improved significantly after land certification. The results should encourage policy makers to minimize the sources of insecurity, such as frustrations of future land redistribution and land taking without proper land compensation. Land certification is the right tool for creating tenure security, enhancing farmers’ confidence in their land rights and—supported by a proper land use planning system—improving land-related investments and crop productivity.
Sharing Property Sharing Labour: The Co-Production of Value in Platform Economies
Authors: Zhu Sally
Published: October 2020

The recent meteoric rise of innovative companies in the sharing economy has divided commentators and regulators alike on the question of their socio-economic impact. Do these economic activities herald an equitable and sustainable alternative to existing practices, or are they simply expanding commercial exploitation into greater areas of life? This dichotomy overlooks how these economic activities constitute new assemblages of labour and property, and shape the flow of value amongst their participants. I propose a conceptual mechanism of ‘labour-service’, whereby labour and value flow through webs of material objects, as a way of examining how organic collaboration is first structured by the laws of property, and then by the dynamics of nascent platform economies. Tracing labour-service through the sharing economy renders a clearer view of the factors that drive collaboration and exploitation, and hopefully can contribute towards more efficacious regulatory measures and advance academic commentary on this emerging phenomenon.
Metallurgical Characterization of Welded Joint of Nanostructured Bainite: Regeneration Technique versus Post Welding Heat Treatment
Authors: Królicka Aleksandra , Radwański Krzysztof , Janik Aleksandra , Kustroń Paweł , Ambroziak Andrzej
Published: October 2020

One of the main limitations in application of nanostructured carbide-free bainite as a construction material is the difficulty of joining. This research presents a structural characterization of welded joints of medium carbon 55Si7 grade steel after the welding process with a regeneration technique as well as post welding heat treatment (PWHT). The hardness distribution of the welded joint with regeneration exhibit an overall decrease in hardness when compared to the base material and a significant decrease in hardness was observed in the heat-affected zone (HAZ). Unfavorable hardness distribution was caused by the presence of diffusion-type transformations products (pearlite) in the HAZ and bainite degradation processes. On the other hand, welding with the PWHT promotes the achievement of a comparable level of hardness and structure as in the base material. However, a slight decrease in hardness was observed in the weld zone due to the micro-segregation of the chemical composition caused by the indissoluble solidification structure. Based on the structural analysis, it was found that steel with relatively low hardenability (55Si7) should be welded using PWHT rather than a regeneration technique.
A Comparison of 3D and 2D FE Frictional Heating Models for Long and Variable Applications of Railway Tread Brake
Authors: Kuciej Michal , Grzes Piotr , Wasilewski Piotr
Published: October 2020

The article proposes two 3D and 2D numerical FE models of frictional heating for the estimation of temperature distributions in railway tread brake in 1xBg configuration during repeated long-term braking. The results of computations were compared with the time courses of temperature measured using thermocouples throughout the duration of the tests on a full-scale dynamometer for two different brake shoe materials in combination with a steel wheel. The resulting temperature distributions calculated using the proposed models agreed well with the experimental measurements, and the maximum difference in temperature values does not exceed 20%. It has been proven that 2D FE model can be as efficient as 3D model to estimate the temperature distribution during long-term and variable braking in the considered friction node. The differences in the calculation of the temperature values using these models did not exceed 3%, and the calculation time for the 2D model, compared to the 3D model, was shorter approximately 85 times for the braking cycle lasting 5032 s, and approximately 45 times for the braking cycle lasting 3297 s.
Parametric Study on In Situ Laser Powder Bed Fusion of Mo(Si1−x,Alx)2
Authors: Minasyan T. , Aydinyan S. , Toyserkani E. , Hussainova I.
Published: October 2020

Mo(Si1−x,Alx)2 composites were produced by a pulsed laser reactive selective laser melting of MoSi2 and 30 wt.% AlSi10Mg powder mixture. The parametric study, altering the laser power between 100 and 300 W and scan speed between 400 and 1500 mm·s−1, has been conducted to estimate the effect of processing parameters on printed coupon samples’ quality. It was shown that samples prepared at 150–200 W laser power and 400–500 mm·s−1 scan speed, as well as 250 W laser power along with 700 mm·s−1 scan speed, provide a relatively good surface finish with 6.5 ± 0.5 µm–10.3 ± 0.8 µm roughness at the top of coupons, and 9.3 ± 0.7 µm–13.2 ± 1.1 µm side surface roughness in addition to a remarkable chemical and microstructural homogeneity. An increase in the laser power and a decrease in the scan speed led to an apparent improvement in the densification behavior resulting in printed coupons of up to 99.8% relative density and hardness of ~600 HV1 or ~560 HV5. The printed parts are composed of epitaxially grown columnar dendritic melt pool cores and coarser dendrites beyond the morphological transition zone in overlapped regions. An increase in the scanning speed at a fixed laser power and a decrease in the power at a fixed scan speed prohibited the complete single displacement reaction between MoSi2 and aluminum, leading to unreacted MoSi2 and Al lean hexagonal Mo(Si1−x,Alx)2 phase.
The Evolution in Electrochemical Performance of Honeycomb-Like Ni(OH)2 Derived from MOF Template with Morphology as a High-Performance Electrode Material for Supercapacitors
Authors: Li Xiao , Li Jun , Zhang Ying , Zhao Peng , Lei Ruyan , Yuan Baige , Xia Manman
Published: October 2020

Ni(OH)2 derived from an MOF template was synthesized as an electrode material for supercapacitors. The electrochemical performance of the electrode was adjusted by effectively regulating the morphology of Ni(OH)2. The evolution of electrochemical performance of the electrode with morphology of Ni(OH)2 was highlighted in detail, based on which honeycomb-like Ni(OH)2 was successfully synthesized, and endowed the electrode with outstanding electrochemical performance. For the three-electrode testing system, honeycomb-like Ni(OH)2 exhibited a very high specific capacitance (1865 F·g−1 at 1 A·g−1, 1550 F·g−1 at 5 mV·s−1). Moreover, it also presented an excellent rate capability and cycling stability, due to 59.46 % of the initial value (1 A·g−1) being retained at 10 A·g−1, and 172% of initial value (first circle at 50 mV·s−1) being retained after 20,000 cycles. With respect to the assembled hybrid supercapacitor, honeycomb-like Ni(OH)2 also displayed superior electrochemical performance, with a high energy density (83.9 Wh·kg−1 at a power density of 374.8 W·kg−1). The outstanding electrochemical performance of Ni(OH)2 should be attributed to its unique honeycomb-like structure, with a very high specific surface area, which greatly accelerates the transformation and diffusion of active ions.
A Novel Method for Changing the Dynamics of Slender Elements Using Sponge Particles Structures
Authors: Żurawski Mateusz , Chiliński Bogumił , Zalewski Robert
Published: October 2020

The paper concerns problems related to controlling the dynamic properties of beam-like elements. The parameters of the investigated system can be changed by external factors, resulting in partial changes in the system mass redistribution. It is assumed that it is possible to control the system dynamics by shaping the object frequency structure. The paper introduces the mathematical model of the investigated cantilever beam filled with a Sponge Particle Structure. The continuous model has been simplified to a discrete multi-degree of freedom system. The influence of the system parameters on its behavior is discussed in details. The possible applications of the presented concept are proposed. The spectral vibration analyses were carried out. Theoretical considerations enabled the use of the preliminary semi-active method for controlling the vibration frequencies through a mass redistribution. Experimental studies were carried out to verify the proposed mathematical model.
Numerical Modeling Design for the Hybrid Additive Manufacturing of Laser Directed Energy Deposition and Shot Peening Forming Fe–Cr–Ni–B–Si Alloy
Authors: Zhang Xiaoyu , Li Dichen , Zhu Weijun
Published: October 2020

Hybrid additive manufacturing is of great significance to make up for the deficiency of the metal forming process; it has been one of the main trends of additive manufacturing in recent years. The hybrid process of laser directed energy deposition (laser DED) and shot peening is a new technology combining the principles of surface strengthening and additive manufacturing, whose difficulty is to reduce the interaction between the two processes. In this paper, a new model with a discrete phase and fluid–solid interaction method is established, and the location of the shot peening point in the hybrid process is optimized. The distributions of the temperature field and powder trajectory were researched and experiments were carried out with the optimized parameters to verify simulation results. It was found that the temperature field and the powder trajectory partly change, and the optimized injection point is located in the stress relaxation zone of the material. The densities and surface residual stresses of samples were improved, and the density increased by 8.83%. The surface stress changed from tensile stress to compressive stress, and the introduced compressive stress by shot peening was 2.26 times the tensile stress produced by laser directed energy deposition.
Optimizing Laser Powder Bed Fusion Parameters for IN-738LC by Response Surface Method
Authors: Vilanova Mireia , Escribano-García Rubén , Guraya Teresa , San Sebastian Maria
Published: October 2020

A method to find the optimum process parameters for manufacturing nickel-based superalloy Inconel 738LC by laser powder bed fusion (LPBF) technology is presented. This material is known to form cracks during its processing by LPBF technology; thus, process parameters have to be optimized to get a high quality product. In this work, the objective of the optimization was to obtain samples with fewer pores and cracks. A design of experiments (DoE) technique was implemented to define the reduced set of samples. Each sample was manufactured by LPBF with a specific combination of laser power, laser scan speed, hatch distance and scan strategy parameters. Using the porosity and crack density results obtained from the DoE samples, quadratic models were fitted, which allowed identifying the optimal working point by applying the response surface method (RSM). Finally, five samples with the predicted optimal processing parameters were fabricated. The examination of these samples showed that it was possible to manufacture IN738LC samples free of cracks and with a porosity percentage below 0.1%. Therefore, it was demonstrated that RSM is suitable for obtaining optimum process parameters for IN738LC alloy manufacturing by LPBF technology.
Towards High Molecular Weight Furan-Based Polyesters: Solid State Polymerization Study of Bio-Based Poly(Propylene Furanoate) and Poly(Butylene Furanoate)
Authors: Papadopoulos Lazaros , Xanthopoulou Eleftheria , Nikolaidis George N. , Zamboulis Alexandra , Achilias Dimitris S. , Papageorgiou George Z. , Bikiaris Dimitrios N.
Published: October 2020

In the era of polymers from renewable resources, polyesters derived from 2,5 furan dicarboxylic acid (FDCA) have received increasing attention due to their outstanding features. To commercialize them, it is necessary to synthesize high molecular weight polymers through efficient and simple methods. In this study, two furan-based polyesters, namely poly (propylene furanoate) (PPF) and poly(butylene furanoate) (PBF), were synthesized with the conventional two-step melt polycondensation, followed by solid-state polycondensation (SSP) conducted at different temperatures and reaction times. Molecular weight, structure and thermal properties were measured for all resultant polyesters. As expected, increasing SSP time and temperature results in polymers with increased intrinsic viscosity (IV), increased molecular weight and reduced carboxyl end-group content. Finally, those results were used to generate a simple mathematical model that prognosticates the time evolution of the materials’ IV and end groups concentration during SSP.
A Genetic Algorithm for the Shelf-Space Allocation Problem with Vertical Position Effects
Authors: Czerniachowska Kateryna , Hernes Marcin
Published: October 2020

The shelf-space on which products are displayed is one of the most important resources in the retail environment. Therefore, decisions about shelf-space allocation and optimization are critical in retail operation management. This paper addresses the problem of a retailer who sells various products by displaying them on the shelf at stores. We present a practical shelf-space allocation model, based on a genetic algorithm, with vertical position effects with the objective of maximizing the retailer’s profit. The validity of the model is illustrated with example problems and compared to the CPLEX solver. The results obtained from the experimental phase show the suitability of the proposed approach.
On Hyperstability of the Cauchy Functional Equation in n-Banach Spaces
Authors: Brzdęk Janusz , El-hady El-sayed
Published: October 2020

We present some hyperstability results for the well-known additive Cauchy functional equation f(x+y)=f(x)+f(y) in n-normed spaces, which correspond to several analogous outcomes proved for some other spaces. The main tool is a recent fixed-point theorem.
Primary Melanoma of the Lung: A Systematic Review
Authors: Paliogiannis Panagiotis , Fara Antonella M. , Pintus Gianfranco , Abdel-Rahman Wael M. , Colombino Maria , Casula Milena , Palmieri Giuseppe , Cossu Antonio
Published: October 2020

Background and Objectives: The respiratory apparatus, generally affected by highly aggressive tumors like lung cancer and mesothelioma, is rarely affected by primary malignant melanoma. The aim of this review was to identify cases of primary malignant melanoma of the lung (PMML) published in the modern scientific literature, and to describe their main clinical, pathological and therapeutic features. Materials and Methods: A systematic search of publications in the electronic database PubMed has been performed using keywords, and the references of the selected articles were checked to identify additional missing studies. Results: Globally 52 papers reporting on 76 cases were identified. Among them there were 47 reports of a single case, three papers reporting on two cases each, and two larger case series published in 1997 and 2005 including eight and 15 cases, respectively. Conclusions: PMML was generally diagnosed in middle-aged males, without any apparent correlation with cigarette smoking. It was more frequently found in the lower lobes and the left lung. The tumors were generally pigmented, composed by epithelial and/or spindle cells with large nuclei and prominent nucleoli, nuclear atypia, and numerous mitotic figures; they commonly showed immunostaining for S-100, HMB 45 and Melan-A. Early detection and surgical resection were the main determinants of survival from this rare malignancy.
Prevalence of Low Back Pain among Nursing Staff in Najran, Saudi Arabia: A Cross-Sectional Study
Authors: Alshahrani Adel
Published: October 2020

This study aimed to determine the various demographic and work-related professional characteristics associated with low back pain among nursing professionals in Najran, Saudi Arabia. A self-administered modified questionnaire (electronic), which included information on general subject demographics and work conditions, was sent through various electronic channels to which 187 nurses working across various health institutions in the Najran region responded. Among the included respondents, 35.3% were Saudis, 64.7% were Non-Saudis, and 88.8% were in the young to middle-age group (21–40 years). Similarly, 57.8% were females, while a majority (91%) had completed a bachelor’s degree. In total, 140 respondents (74.8%) reported experiencing low back pain. Among the various work-related factors, gender, place of work, nature of work, and direct contact hours with patients per week were found to be significantly associated with low back pain. Assessment of pain characteristics found that a majority (88.2%) had mild to moderate localized back pain. A significant number of nursing professionals included herein reported to have low back pain, which appeared to be moderated by work-related characteristics, including place and nature of work. Our findings can help to establish policies and interventions aimed at reducing the risk and onset of low back pain.
Mechanical Behaviour of an Al2O3 Dispersion Strengthened γTiAl Alloy Produced by Centrifugal Casting
Authors: Pilone Daniela , Pulci Giovanni , Paglia Laura , Mondal Avishek , Marra Francesco , Felli Ferdinando , Brotzu Andrea
Published: October 2020

γ-TiAl has been a hot topic of research for more than a few decades now, since it is a potential candidate for high temperature structural applications. In this paper, dispersion strengthening of γ based TiAl alloy, produced by means of centrifugal casting, has been performed to increase its mechanical properties beyond those of standard TiAl alloys. After a careful selection of the alloy composition based on the desired properties, several samples were produced by means of investment casting. This work focused on the effect of Al2O3 nano- and micro-dispersoids on the mechanical properties of the considered TiAl alloy. Microstructural investigations were carried out to study both the alloy microstructure and the Al2O3 dispersion homogeneity. Samples of the produced alloy were subjected to four-point bending tests at different temperatures for evaluating the effect of dispersed particles on mechanical properties. The results of this study were promising and showed that Al2O3 dispersion determined an increase of the mechanical properties at high temperatures. The Young’s modulus was 30% higher than that of the reference alloy in the lower temperature range. Over the temperature range 800–950 °C the dispersion strengthening affected the yield stress by increasing its value of about 20% even at 800 °C. A detailed evaluation of fracture surfaces was carried out to investigate fracture mechanisms.
Multiplexed Quantitative Assessment of the Fate of Taurine and Sulfoquinovose in the Intestinal Microbiome
Authors: Haange Sven-Bastiaan , Groeger Nicole , Froment Jean , Rausch Theresa , Burkhardt Wiebke , Gonnermann Svenja , Braune Annett , Blaut Michael , von Bergen Martin , Rolle-Kampczyk Ulrike
Published: October 2020

(1) Introduction: Sulfonates, which can be diet- or host-derived, are a class of compounds detected in the gut, are involved in host–microbiome interactions and have several health effects. Our aim was to develop a method to quantify five of the sulfonates in the intestine and apply it in a simplified human microbiome model. These were taurine, its metabolic precursor cysteate and one of its degradation products isethionate, as well as sulfoquinovose and one of its most relevant degradation products 2,3-dihydroxy-1-propanesulfonate. (2) Methods: An extraction and sample preparation method was developed, without the need for derivatization. To detect and quantify the extracted sulfonates, a multiplexed LC-MS/MS-MRM method was established. (3) Results: The accuracy and precision of the method were within GLP-accepted parameters. To apply this method in a pilot study, we spiked either taurine or sulfoquinovose into an in vitro simplified human microbiota model with and without Bilophila wadsworthia, a known sulfonate utilizer. The results revealed that only the culture with B. wadsworthia was able to degrade taurine, with isethionate as an intermediate. After spiking the communities with sulfoquinovose, the results revealed that the simplified human microbiome model was able to degrade sulfoquinovose to 2,3-dihydroxypropane-1-sulfonate, which was probably catalyzed by Escherichia coli. In the community with B. wadsworthia, the 2,3-dihydroxypropane-1-sulfonate produced was further degraded by B. wadsworthia to sulfide. (4) Conclusions: We successfully developed a method for sulfonate quantification and applied it in a first pilot study.
Characterization of Soft Tooling Photopolymers and Processes for Micromixing Devices with Variable Cross-Section
Authors: Martínez-López J. Israel , Betancourt Cervantes Héctor Andrés , Cuevas Iturbe Luis Donaldo , Vázquez Elisa , Naula Edisson A. , Martínez López Alejandro , Siller Héctor R. , Mendoza-Buenrostro Christian , Rodríguez Ciro A.
Published: October 2020

In this paper, we characterized an assortment of photopolymers and stereolithography processes to produce 3D-printed molds and polydimethylsiloxane (PDMS) castings of micromixing devices. Once materials and processes were screened, the validation of the soft tooling approach in microfluidic devices was carried out through a case study. An asymmetric split-and-recombine device with different cross-sections was manufactured and tested under different regime conditions (10 < Re < 70). Mixing performances between 3% and 96% were obtained depending on the flow regime and the pitch-to-depth ratio. The study shows that 3D-printed soft tooling can provide other benefits such as multiple cross-sections and other potential layouts on a single mold.
A 2D Waveguide Method for Lithography Simulation of Thick SU-8 Photoresist
Authors: Geng Zi-Chen , Zhou Zai-Fa , Dai Hui , Huang Qing-An
Published: October 2020

Due to the increasing complexity of microelectromechanical system (MEMS) devices, the accuracy and precision of two-dimensional microstructures of SU-8 negative thick photoresist have drawn more attention with the rapid development of UV lithography technology. This paper presents a high-precision lithography simulation model for thick SU-8 photoresist based on waveguide method to calculate light intensity in the photoresist and predict the profiles of developed SU-8 structures in two dimension. This method is based on rigorous electromagnetic field theory. The parameters that have significant influence on profile quality were studied. Using this model, the light intensity distribution was calculated, and the final resist morphology corresponding to the simulation results was examined. A series of simulations and experiments were conducted to verify the validity of the model. The simulation results were found to be in good agreement with the experimental results, and the simulation system demonstrated high accuracy and efficiency, with complex cases being efficiently handled.
Surface-Tension-Confined Channel with Biomimetic Microstructures for Unidirectional Liquid Spreading
Authors: Zhang Yi , Gan Yang , Zhang Liwen , Zhang Deyuan , Chen Huawei
Published: October 2020

Unidirectional liquid spreading without energy input is of significant interest for the broad applications in diverse fields such as water harvesting, drop transfer, oil–water separation and microfluidic devices. However, the controllability of liquid motion and the simplification of manufacturing process remain challenges. Inspired by the peristome of Nepenthes alata, a surface-tension-confined (STC) channel with biomimetic microcavities was fabricated facilely through UV exposure photolithography and partial plasma treatment. Perfect asymmetric liquid spreading was achieved by combination of microcavities and hydrophobic boundary, and the stability of pinning effect was demonstrated. The influences of structural features of microcavities on both liquid spreading and liquid pinning were investigated and the underlying mechanism was revealed. We also demonstrated the spontaneous unidirectional transport of liquid in 3D space and on tilting slope. In addition, through changing pits arrangement and wettability pattern, complex liquid motion paths and microreactors were realized. This work will open a new way for liquid manipulation and lab-on-chip applications.
Eradication of Saccharomyces cerevisiae by Pulsed Electric Field Treatments
Authors: Emanuel Efrat , Dubrovin Irina , Hanya Ester , Pinhasi Gad A. , Pogreb Roman , Cahan Rivka
Published: October 2020

One of the promising technologies that can inactivate microorganisms without heat is pulsed electric field (PEF) treatment. The aim of this study was to examine the influence of PEF treatment (2.9 kV cm−1, 100 Hz, 5000 pulses in trains mode of 500 pulses with a pulse duration of 10 µs) on Saccharomyces cerevisiae eradication and resealing in different conditions, such as current density (which is influenced by the medium conductivity), the sort of medium (phosphate buffered saline (PBS) vs. yeast malt broth (YMB) and a combined treatment of PEF with the addition of preservatives. When the S. cerevisiae were suspended in PBS, increasing the current density from 0.02 to 3.3 A cm−2 (corresponding to a total specific energy of 22.04 to 614.59 kJ kg−1) led to an increase of S. cerevisiae eradication. At 3.3 A cm−2, a total S. cerevisiae eradication was observed. However, when the S. cerevisiae in PBS was treated with the highest current density of 3.3 A cm−2, followed by dilution in a rich YMB medium, a phenomenon of cell membrane resealing was observed by flow cytometry (FCM) and CFU analysis. The viability of S. cerevisiae was also examined when the culture was exposed to repeating PEF treatments (up to four cycles) with and without the addition of preservatives. This experiment was performed when the S. cerevisiae were suspended in YMB containing tartaric acid (pH 3.4) and ethanol to a final concentration of 10% (v/v), which mimics wine. It was shown that one PEF treatment cycle led to a reduction of 1.35 log10, compared to 2.24 log10 when four cycles were applied. However, no synergic effect was observed when the preservatives, free SO2, and sorbic acid were added. This study shows the important and necessary knowledge about yeast eradication and membrane recovery processes after PEF treatment, in particular for application in the liquid food industry.
Lysogenization of a Lactococcal Host with Three Distinct Temperate Phages Provides Homologous and Heterologous Phage Resistance
Authors: Ruiz-Cruz Sofia , Parlindungan Elvina , Erazo Garzon Andrea , Alqarni Mona , Lugli Gabriele A. , Ventura Marco , van Sinderen Douwe , Mahony Jennifer
Published: October 2020

Lactococcus lactis is the most widely exploited microorganism in global dairy fermentations. Lactococcal strains are described as typically harboring a number of prophages in their chromosomes. The presence of such prophages may provide both advantages and disadvantages to the carrying host. Here, we describe the deliberate generation of three distinct lysogens of the model lactococcal strain 3107 and the impact of additional prophage carriage on phage-resistance and anti-microbial susceptibility. Lysogen-specific responses were observed, highlighting the unique relationship and impact of each lysogenic phage on its host. Both homologous and heterologous phage-resistance profiles were observed, highlighting the presence of possible prophage-encoded phage-resistance factors. Superinfection exclusion was among the most notable causes of heterologous phage-resistance profiles with resistance observed against members of the Skunavirus, P335, P087, and 949 lactococcal phage groups. Through these analyses, it is now possible to identify phages that may pursue similar DNA injection pathways. The generated lysogenic strains exhibited increased sensitivity to the antimicrobial compounds, nisin and lysozyme, relative to the parent strain, although it is noteworthy that the degree of sensitivity was specific to the individual (pro)phages. Overall, the findings highlight the unique impact of each prophage on a given strain and the requirement for strain-level analysis when considering the implications of lysogeny.
Nitrifying Microbes in the Rhizosphere of Perennial Grasses Are Modified by Biological Nitrification Inhibition
Authors: Zhou Yi , Lambrides Christopher J. , Li Jishun , Xu Qili , Toh Ruey , Tian Shenzhong , Yang Peizhi , Yang Hetong , Ryder Maarten , Denton Matthew D.
Published: October 2020

Soil nitrification (microbial oxidation of ammonium to nitrate) can lead to nitrogen leaching and environmental pollution. A number of plant species are able to suppress soil nitrifiers by exuding inhibitors from roots, a process called biological nitrification inhibition (BNI). However, the BNI activity of perennial grasses in the nutrient-poor soils of Australia and the effects of BNI activity on nitrifying microbes in the rhizosphere microbiome have not been well studied. Here we evaluated the BNI capacity of bermudagrass (Cynodon dactylon L.), St. Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze), saltwater couch (Sporobolus virginicus), seashore paspalum (Paspalum vaginatum Swartz.), and kikuyu grass (Pennisetum clandestinum) compared with the known positive control, koronivia grass (Brachiaria humidicola). The microbial communities were analysed by sequencing 16S rRNA genes. St. Augustinegrass and bermudagrass showed high BNI activity, about 80 to 90% of koronivia grass. All the three grasses with stronger BNI capacities suppressed the populations of Nitrospira in the rhizosphere, a bacteria genus with a nitrite-oxidizing function, but not all of the potential ammonia-oxidizing archaea. The rhizosphere of saltwater couch and seashore paspalum exerted a weak recruitment effect on the soil microbiome. Our results demonstrate that BNI activity of perennial grasses played a vital role in modulating nitrification-associated microbial populations.
Seroprevalence of Borrelia burgdorferi in Stray Dogs from Southern Italy
Authors: Galluzzo Paola , Grippi Francesca , Di Bella Santina , Santangelo Francesco , Sciortino Sonia , Castiglia Alessandra , Sciacca Carmela , Arnone Maria , Alduina Rosa , Chiarenza Giuseppina
Published: October 2020

Borrelia burgdorferi is a bacterial pathogen transmitted by Ixodes ticks and is responsible for Lyme disease in both humans and dogs. The aim of this work was to evaluate B. burgdorferi diffusion among stray dogs in Palermo (Sicily, Italy) by serological methods in order to study the risk factors associated with the infection. Serum and blood samples of 316 dogs were collected from a shelter in Palermo, and were analyzed for the presence of antibodies against B. burgdorferi by indirect immunofluorescence assay (IFA), and of the ospA gene by real-time PCR, respectively. Seventeen sera (5.4%) were positive for the antibodies via IFA and one blood (0.3%) for ospA via real time PCR. On the basis of serological results, the evaluation of the potential risk factors (sex, age, breed and coat color) was carried out. The multivariate analysis indicated that male sex is a factor significantly associated with B. burgdorferi seropositivity. This study confirms that male dogs have a higher risk of developing the disease than females, and represents the first investigation on the spread of B. burgdorferi among stray dogs in Sicily.
Comparison of Campylobacter jejuni Slaughterhouse and Surface-Water Isolates Indicates Better Adaptation of Slaughterhouse Isolates to the Chicken Host Environment
Authors: Šimunović Katarina , Zajkoska Sandra , Bezek Katja , Klančnik Anja , Barlič Maganja Darja , Smole Možina Sonja
Published: October 2020

Campylobacter jejuni is an emerging food-borne pathogen that poses a high risk to human health. Knowledge of the strain source can contribute significantly to an understanding of this pathogen, and can lead to improved control measures in the food-processing industry. In this study, slaughterhouse and surface-water isolates of C. jejuni were characterized and compared in terms of their antimicrobial resistance profiles and adhesion to stainless steel and chicken skin. Resistance of C. jejuni biofilm cells to benzalkonium chloride and Satureja montana ethanolic extract was also tested. The data show that the slaughterhouse isolates are more resistant to ciprofloxacin, and adhere better to stainless steel at 42 °C, and at 37 °C in 50% chicken juice. Additionally, biofilm cells of the isolate with the greatest adhesion potential (C. jejuni S6) were harvested and tested for resistance to S. montana ethanolic extract, benzalkonium chloride, and erythromycin; and for efflux-pump activity, as compared to their planktonic cells. The biofilm cells showed increased resistance to both S. montana ethanolic extract and erythromycin, and increased efflux-pump activity. These data indicate adaptation of C. jejuni slaughterhouse isolates to the chicken host, as well as increased biofilm cell resistance due to increased efflux-pump activity.