Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume

Journal Name	Impact Factor	CiteScore	Launched Year	First Decision (median)	APC
Foods foods	4.7	7.4	2012	14.3 Days	CHF 2900
Materials materials	3.1	5.8	2008	15.5 Days	CHF 2600
Polymers polymers	4.7	8.0	2009	14.5 Days	CHF 2700
Sensors sensors	3.4	7.3	2001	16.8 Days	CHF 2600
Sustainability sustainability	3.3	6.8	2009	20 Days	CHF 2400

16 pages, 5283 KiB

Open AccessArticle

Approach to the Fatigue and Cellular Behavior of Superficially Modified Porous Titanium Dental Implants

by Paloma Trueba, Carlos Navarro, Mercè Giner, José A. Rodríguez-Ortiz, María José Montoya-García, Ernesto J. Delgado-Pujol, Luisa M. Rodríguez-Albelo and Yadir Torres

Materials 2022, 15(11), 3903; https://doi.org/10.3390/ma15113903 - 30 May 2022

Cited by 5 | Viewed by 1755

Abstract

In this work, the fatigue and cellular performance of novel superficially treated porous titanium dental implants made up using conventional powder metallurgy and space-holder techniques (30 vol.% and 50 vol.%, both with a spacer size range of 100–200 µm) are evaluated. Before the [...] Read more.

In this work, the fatigue and cellular performance of novel superficially treated porous titanium dental implants made up using conventional powder metallurgy and space-holder techniques (30 vol.% and 50 vol.%, both with a spacer size range of 100–200 µm) are evaluated. Before the sintering stage, a specific stage of CNC milling of the screw thread of the implant is used. After the consolidation processing, different surface modifications are performed: chemical etching and bioactive coatings (BG 45S5 and BG 1393). The results are discussed in terms of the effect of the porosity, as well as the surface roughness, chemical composition, and adherence of the coatings on the fatigue resistance and the osteoblast cells’ behavior for the proposed implants. Macro-pores are preferential sites of the nucleation of cracks and bone cell adhesion, and they increase the cellular activity of the implants, but decrease the fatigue life. In conclusion, SH 30 vol.% dental implant chemical etching presents the best bio-functional (in vitro osseointegration) and bio-mechanical (stiffness, yield strength and fatigue life) balance, which could ensure the required characteristics of cortical bone tissue. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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17 pages, 3671 KiB

Open AccessArticle

Optimization of Multiple W₁/O/W₂ Emulsions Processing for Suitable Stability and Encapsulation Efficiency

by Manuel Felix, Antonio Guerrero and Cecilio Carrera-Sánchez

Foods 2022, 11(9), 1367; https://doi.org/10.3390/foods11091367 - 9 May 2022

Cited by 6 | Viewed by 2333

Abstract

Double emulsions are a type of multiple emulsions, which can be defined as a multicompartmentalized system where the droplets are dispersed into the continuous phase containing other emulsions. Although double food-grade emulsions have been manufactured, there is a lack of scientific background related [...] Read more.

Double emulsions are a type of multiple emulsions, which can be defined as a multicompartmentalized system where the droplets are dispersed into the continuous phase containing other emulsions. Although double food-grade emulsions have been manufactured, there is a lack of scientific background related to the influence of different processing conditions. This work analyses the influence of processing variables in (W₁/O/W₂) double emulsions: passes through the valve homogenizer, pressure applied, lipophilic emulsifier concentration, the ratio between the continuous phase (W₂) and the primary emulsion (W₁/O), and the incorporation of xanthan gum (XG) as a stabilizer. The results obtained show that these emulsions can be obtained after selecting suitable processing conditions, making them easily scalable in industrial processes. In terms of droplet size distribution, the input of higher energy to the system (20 MPa) during emulsification processing led to emulsions with smaller droplet sizes (D_3,2). However, more monodispersed emulsions were achieved when the lowest pressure (5 MPa) was used. As for the number of passes, the optimal (emulsions more monodispersed and smaller droplet sizes) was found around 2–3 passes, regardless of the valve homogenizer pressure. However, emulsions processed at 20 MPa involved lower encapsulation efficiency (E_E) than emulsions processed at 5 MPa (87.3 ± 2.3 vs. 96.1 ± 1.8, respectively). The addition of XG led to more structured emulsions, and consequently, their kinetic stability increased. The results obtained indicated that a correct formulation of these W₁/O/W₂ double emulsions allowed the optimal encapsulation of both hydrophilic and lipophilic bioactive compounds. Thus, the development of food matrices, in the form of multiple emulsions, would allow the encapsulation of bioactive compounds, which would result in the development of novelty food products. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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Droplet size of W1/O/W2 multiple emulsions obtained after processing the secondary emulsion at 5 MPa (A) and 20 MPa (B), as a function emulsion passes through the high-pressure homogenizer. Full article ">Figure 2
Droplet size distribution of W1/O/W2 multiple emulsions obtained after using 1, 3 and 5 wt.% PGPR for the primary emulsion. Full article ">Figure 3
Droplet size distribution of W1/O/W2 multiple emulsions obtained after three different O/W ratios for the secondary emulsion: 10/90 (A), 25/75 (B) and 40/60 (C). Full article ">Figure 4
Changes in backscattering profiles (DBS%) as a function of sample height with storage time of W1/O/W2 multiple emulsions obtained after three different O/W ratios for the secondary emulsion: 40/60 (A), 25/75 (B) and 10/90 (C). The arrows indicate the storage time. Full article ">Figure 5
Complex moduli (G*) of multiple emulsions as a function of frequency obtained for three different (W1/O)/W2 ratios for the secondary emulsion: 10/90, 25/75 and 40/60. Full article ">Figure 6
Backscattering profiles of W1/O/W2 multiple emulsions obtained at two different xanthan gum (XG) concentrations: 0 (A), 0.125 (B) and 0.25 (C) wt.%. Full article ">Figure 7
Viscoelastic moduli (G′ and G″) as a function of frequency of W1/O/W2 multiple emulsions obtained at three different xanthan gum (XG) concentrations (0, 0.125 and 0.25 wt.%) obtained the same day emulsion preparation. Full article ">

19 pages, 720 KiB

Open AccessArticle

Research on Collaborative Innovation Mode of Enterprise Group from the Perspective of Comprehensive Innovation Management

by Wei Feng, Ling Zhao and Yue Chen

Sustainability 2022, 14(9), 5304; https://doi.org/10.3390/su14095304 - 28 Apr 2022

Cited by 8 | Viewed by 2825

Abstract

At present, collaborative innovation has become an integral part of corporate group strategy. However, there are few collaborative innovation research pieces focusing on corporate groups. This article takes Tus-Holdings, a model enterprise in the field of science and technology services, as the research [...] Read more.

At present, collaborative innovation has become an integral part of corporate group strategy. However, there are few collaborative innovation research pieces focusing on corporate groups. This article takes Tus-Holdings, a model enterprise in the field of science and technology services, as the research object, uses case study methods, and systematically analyzes the corporate group’s strategy, customers, R&D, management, finance, talent, and other factors from the strategic, business, and support levels under the framework of total innovation management research on the collaborative innovation model of management and the form of cooperative surplus. The research found that the collaborative innovation model is an important support for enterprise groups to build a comprehensive, collaborative innovation system; the internal collaborative innovation model of enterprise groups shows nonlinearity and diversity; collaborative surplus performance is closely related to the collaborative innovation mode, and different collaborative innovation modes will produce a different collaborative surplus. These research results have important theoretical value and practical significance for modern enterprise groups to correctly implement collaborative innovation strategy and improve the efficiency of collaborative innovation. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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17 pages, 7443 KiB

Open AccessArticle

Influence of Femtosecond Laser Modification on Biomechanical and Biofunctional Behavior of Porous Titanium Substrates

by Ana M. Beltrán, Mercè Giner, Ángel Rodríguez, Paloma Trueba, Luisa M. Rodríguez-Albelo, Maria Angeles Vázquez-Gámez, Vanda Godinho, Ana Alcudia, José M. Amado, Carmen López-Santos and Yadir Torres

Materials 2022, 15(9), 2969; https://doi.org/10.3390/ma15092969 - 19 Apr 2022

Cited by 3 | Viewed by 2243

Abstract

Bone resorption and inadequate osseointegration are considered the main problems of titanium implants. In this investigation, the texture and surface roughness of porous titanium samples obtained by the space holder technique were modified with a femtosecond Yb-doped fiber laser. Different percentages of porosity [...] Read more.

Bone resorption and inadequate osseointegration are considered the main problems of titanium implants. In this investigation, the texture and surface roughness of porous titanium samples obtained by the space holder technique were modified with a femtosecond Yb-doped fiber laser. Different percentages of porosity (30, 40, 50, and 60 vol.%) and particle range size (100–200 and 355–500 μm) were compared with fully-dense samples obtained by conventional powder metallurgy. After femtosecond laser treatment the formation of a rough surface with micro-columns and micro-holes occurred for all the studied substrates. The surface was covered by ripples over the micro-metric structures. This work evaluates both the influence of the macro-pores inherent to the spacer particles, as well as the micro-columns and the texture generated with the laser, on the wettability of the surface, the cell behavior (adhesion and proliferation of osteoblasts), micro-hardness (instrumented micro-indentation test, P–h curves) and scratch resistance. The titanium sample with 30 vol.% and a pore range size of 100–200 μm was the best candidate for the replacement of small damaged cortical bone tissues, based on its better biomechanical (stiffness and yield strength) and biofunctional balance (bone in-growth and in vitro osseointegration). Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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13 pages, 2114 KiB

Open AccessArticle

Cost Function Analysis Applied to Different Kinetic Release Models of Arrabidaea chica Verlot Extract from Chitosan/Alginate Membranes

by Luis Concha, Ana Luiza Resende Pires, Angela Maria Moraes, Elizabeth Mas-Hernández, Stefan Berres and Jacobo Hernandez-Montelongo

Polymers 2022, 14(6), 1109; https://doi.org/10.3390/polym14061109 - 10 Mar 2022

Cited by 13 | Viewed by 2553

Abstract

This work focuses on the mathematical analysis of the controlled release of a standardized extract of A. chica from chitosan/alginate (C/A) membranes, which can be used for the treatment of skin lesions. Four different types of C/A membranes were tested: a dense membrane [...] Read more.

This work focuses on the mathematical analysis of the controlled release of a standardized extract of A. chica from chitosan/alginate (C/A) membranes, which can be used for the treatment of skin lesions. Four different types of C/A membranes were tested: a dense membrane (CA), a dense and flexible membrane (CAS), a porous membrane (CAP) and a porous and flexible membrane (CAPS). The Arrabidae chica extract release profiles were obtained experimentally in vitro using PBS at 37 °C and pH 7. Experimental data of release kinetics were analyzed using five classical models from the literature: Zero Order, First Order, Higuchi, Korsmeyer–Peppas and Weibull functions. Results for the Korsmeyer–Peppas model showed that the release of A. chica extract from four membrane formulations was by a diffusion through a partially swollen matrix and through a water filled network mesh; however, the Weibull model suggested that non-porous membranes (CA and CAS) had fractal geometry and that porous membranes (CAP and CAPS) have highly disorganized structures. Nevertheless, by applying an explicit optimization method that employs a cost function to determine the model parameters that best fit to experimental data, the results indicated that the Weibull model showed the best simulation for the release profiles from the four membranes: CA, CAS and CAP presented Fickian diffusion through a polymeric matrix of fractal geometry, and only the CAPS membrane showed a highly disordered matrix. The use of this cost function optimization had the significant advantage of higher fitting sensitivity. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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13 pages, 2064 KiB

Open AccessArticle

Gelatin-Based Biofilms with Fe_xO_y-NPs Incorporated for Antioxidant and Antimicrobial Applications

by Johar Amin Ahmed Abdullah, Mercedes Jiménez-Rosado, Antonio Guerrero and Alberto Romero

Materials 2022, 15(5), 1966; https://doi.org/10.3390/ma15051966 - 7 Mar 2022

Cited by 17 | Viewed by 2670

Abstract

Currently, gelatin-based films are regarded as promising alternatives to non-environmentally friendly plastic films for food packaging. Nevertheless, although they have great biodegradability, their weak mechanical properties and high solubility limit their applications. In this way, the use of nanoparticles, such as Fe_x [...] Read more.

Currently, gelatin-based films are regarded as promising alternatives to non-environmentally friendly plastic films for food packaging. Nevertheless, although they have great biodegradability, their weak mechanical properties and high solubility limit their applications. In this way, the use of nanoparticles, such as Fe_xO_y-NPs, could improve the properties of gelatin-based biofilms. Thus, the main objective of this work was to include different concentrations of Fe_xO_y-NPs (0.25 and 1.0%) manufactured by green synthesis (GS) and chemical synthesis (CS) into gelatin-based biofilms in order to improve their properties. The results show that Fe_xO_y-NPs can be distributed throughout the biofilm, although with a greater concentration on the upper surface. In addition, the incorporation of Fe_xO_y-NPs into the biofilms improves their physicochemical, mechanical, morphological, and biological properties. Thus, it is possible to achieve suitable gelatin-based biofilms, which can be used in several applications, such as functional packaging in the food industry, antioxidant and antimicrobial additives in biomedical and pharmaceutical biomaterials, and in agricultural pesticides. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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26 pages, 39063 KiB

Open AccessArticle

Decision Support System to Classify and Optimize the Energy Efficiency in Smart Buildings: A Data Analytics Approach

by Manuel Peña, Félix Biscarri, Enrique Personal and Carlos León

Sensors 2022, 22(4), 1380; https://doi.org/10.3390/s22041380 - 11 Feb 2022

Cited by 8 | Viewed by 3093

Abstract

In this paper, an intelligent data analysis method for modeling and optimizing energy efficiency in smart buildings through Data Analytics (DA) is proposed. The objective of this proposal is to provide a Decision Support System (DSS) able to support experts in quantifying and [...] Read more.

In this paper, an intelligent data analysis method for modeling and optimizing energy efficiency in smart buildings through Data Analytics (DA) is proposed. The objective of this proposal is to provide a Decision Support System (DSS) able to support experts in quantifying and optimizing energy efficiency in smart buildings, as well as reveal insights that support the detection of anomalous behaviors in early stages. Firstly, historical data and Energy Efficiency Indicators (EEIs) of the building are analyzed to extract the knowledge from behavioral patterns of historical data of the building. Then, using this knowledge, a classification method to compare days with different features, seasons and other characteristics is proposed. The resulting clusters are further analyzed, inferring key features to predict and quantify energy efficiency on days with similar features but with potentially different behaviors. Finally, the results reveal some insights able to highlight inefficiencies and correlate anomalous behaviors with EE in the smart building. The approach proposed in this work was tested on the BlueNet building and also integrated with Eugene, a commercial EE tool for optimizing energy consumption in smart buildings. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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15 pages, 3067 KiB

Open AccessArticle

Effect of Solution Properties in the Development of Cellulose Derivative Nanostructures Processed via Electrospinning

by Pablo Sánchez-Cid, José Fernando Rubio-Valle, Mercedes Jiménez-Rosado, Víctor Pérez-Puyana and Alberto Romero

Polymers 2022, 14(4), 665; https://doi.org/10.3390/polym14040665 - 10 Feb 2022

Cited by 9 | Viewed by 2275

Abstract

In the last few years, electrospinning has proved to be one of the best methods for obtaining membranes of a micro and nanometric fiber size. This method mainly consists in the spinning of a polymeric or biopolymeric solution in solvents, promoted by the [...] Read more.

In the last few years, electrospinning has proved to be one of the best methods for obtaining membranes of a micro and nanometric fiber size. This method mainly consists in the spinning of a polymeric or biopolymeric solution in solvents, promoted by the difference in the electric field between the needle and collector, which is finally deposited as a conjunction of randomly oriented fibers. The present work focuses on using cellulose derivatives (namely cellulose acetate and ethylcellulose), based on the revaluation of these byproducts and waste products of biorefinery, to produce nanostructured nanofiber through electrospinning with the objective of establishing a relation between the initial solutions and the nanostructures obtained. In this sense, a complete characterization of the biopolymeric solutions (physicochemical and rheological properties) and the resulting nanostructures (microstructural and thermal properties) was carried out. Therefore, solutions with different concentrations (5, 10, 15, and 20 wt%) of the two cellulose derivatives and different solvents with several proportions between them were used to establish their influence on the properties of the resulting nanostructures. The results show that the solutions with 10 wt% in acetic acid/H₂O and 15 wt% in acetone/N,N-dimethylformamide of cellulose acetate and 5 wt% of ethylcellulose in acetone/N,N-dimethylformamide, exhibited the best properties, both in the solution and nanostructure state. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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Concentration dependence of the specific viscosity for different solutions of AC and EC with different solvents. Full article ">Figure 2
FTIR spectra of both raw materials (AC and EC) and selected nanostructures of the different systems. The dashed lines marked the most representative peaks that have been analyzed. Full article ">Figure 3
SEM images and distribution of microstructural properties of the nanostructures made with different AC concentrations: (A) 5 wt.%, (B) 10 wt.%, (C) 15 wt.%, and (D) 20 wt.%, using acetic acid and water as solvents. Full article ">Figure 4
SEM images and distribution of microstructural properties of the nanostructures made with different AC concentrations: (A) 5 wt.%, (B) 10 wt.%, (C) 15 wt.%, and (D) 20 wt.%, using acetone and DMF as solvents. Full article ">Figure 5
SEM images and distribution of microstructural properties of the nanostructures made with different EC concentrations (A) 2.5 wt.% and (B) 5 wt.%, using acetone and DMF as solvents. Full article ">Figure 6
Empirical correlation between specific viscosity of solutions with (A) particle diameter and (B) fiber diameter obtained for the AC and EC systems. Full article ">

20 pages, 1299 KiB

Open AccessArticle

Convolutional Neural Networks for Segmenting Cerebellar Fissures from Magnetic Resonance Imaging

by Robin Cabeza-Ruiz, Luis Velázquez-Pérez, Alejandro Linares-Barranco and Roberto Pérez-Rodríguez

Sensors 2022, 22(4), 1345; https://doi.org/10.3390/s22041345 - 10 Feb 2022

Cited by 7 | Viewed by 2366

Abstract

The human cerebellum plays an important role in coordination tasks. Diseases such as spinocerebellar ataxias tend to cause severe damage to the cerebellum, leading patients to a progressive loss of motor coordination. The detection of such damages can help specialists to approximate the [...] Read more.

The human cerebellum plays an important role in coordination tasks. Diseases such as spinocerebellar ataxias tend to cause severe damage to the cerebellum, leading patients to a progressive loss of motor coordination. The detection of such damages can help specialists to approximate the state of the disease, as well as to perform statistical analysis, in order to propose treatment therapies for the patients. Manual segmentation of such patterns from magnetic resonance imaging is a very difficult and time-consuming task, and is not a viable solution if the number of images to process is relatively large. In recent years, deep learning techniques such as convolutional neural networks (CNNs or convnets) have experienced an increased development, and many researchers have used them to automatically segment medical images. In this research, we propose the use of convolutional neural networks for automatically segmenting the cerebellar fissures from brain magnetic resonance imaging. Three models are presented, based on the same CNN architecture, for obtaining three different binary masks: fissures, cerebellum with fissures, and cerebellum without fissures. The models perform well in terms of precision and efficiency. Evaluation results show that convnets can be trained for such purposes, and could be considered as additional tools in the diagnosis and characterization of neurodegenerative diseases. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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Comparison between segmentations on MRI of SCA2 patient. In (a) the original imaging, in (b) segmentation produced by ACAPULCO, and in (c) segmentation obtained by CERES. Full article ">Figure 2
Architecture diagram (a), and inception module pipeline (b). Full article ">Figure 3
Steps of data construction procedure. Sagittal views of the original image (a), cerebellar mask obtained with ACAPULCO (b), result of BFC and registration (c), contrast-enhanced image (d), binary image obtained (e), feature map containing the whole cerebellar tissue (f), obtained fissures mask (g), and cerebellum with fissures (h). In (i) a 3D view of the union of (g,h); red color represents the cerebellar tissue, and green color shows the fissures. Full article ">Figure 4
Masks and predictions for an MRI belonging to one of the SCA2 patients in the test subset. The top row shows the original masks, obtained with the procedure described in <a href="#sec2dot2-sensors-22-01345" class="html-sec">Section 2.2</a>, and the bottom row displays the segmentations produced by our models. Cerebellar fissures in (a,d), cerebellum tissue with fissures in (b,e), and whole cerebellum without any fissure in (c,f). Full article ">Figure 5
Example of segmentations produced by the approaches for a sample image from our dataset. Original mask (a), followed by segmentation produced by M2 (b), CERES (c) and ACAPULCO (d). Full article ">Figure 6
Segmentations produced by the three approaches for a sample image from the DLBS dataset. Original mask (a), followed by segmentation produced by M2 (b), CERES (c) and ACAPULCO (d). Full article ">

22 pages, 821 KiB

Open AccessArticle

Design and Evaluation of a Heterogeneous Lightweight Blockchain-Based Marketplace

by Javier Antonio Guerra, Juan Ignacio Guerrero, Sebastián García, Samuel Domínguez-Cid, Diego Francisco Larios and Carlos León

Sensors 2022, 22(3), 1131; https://doi.org/10.3390/s22031131 - 2 Feb 2022

Cited by 3 | Viewed by 2324

Abstract

The proposal of this paper is to introduce a low-level blockchain marketplace, which is a blockchain where participants could share its power generation and demand. To achieve this implementation in a secure way for each actor in the network, we proposed to deploy [...] Read more.

The proposal of this paper is to introduce a low-level blockchain marketplace, which is a blockchain where participants could share its power generation and demand. To achieve this implementation in a secure way for each actor in the network, we proposed to deploy it over efficient and generic low-performance devices. Thus, they are installed as IoT devices, registering measurements each fifteen minutes, and also acting as blockchain nodes for the marketplace. Nevertheless, it is necessary that blockchain is lightweight, so it is implemented as a specific consensus protocol that allows each node to have enough time and computer requirements to act both as an IoT device and a blockchain node. This marketplace will be ruled by Smart Contracts deployed inside the blockchain. With them, it is possible to make registers for power generation and demand. This low-level marketplace could be connected to other services to execute matching algorithms from the data stored in the blockchain. Finally, a real test-bed implementation of the marketplace was tested, to confirm that it is technically feasible. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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17 pages, 4522 KiB

Open AccessArticle

Processing and Characterization of Bioplastics from the Invasive Seaweed Rugulopteryx okamurae

by Ismael Santana, Manuel Félix, Antonio Guerrero and Carlos Bengoechea

Polymers 2022, 14(2), 355; https://doi.org/10.3390/polym14020355 - 17 Jan 2022

Cited by 24 | Viewed by 5019

Abstract

The seaweed Rugulopteryx okamurae, from the Pacific Ocean, is considered an invasive species in the Mediterranean Sea. In this work, the use of this seaweed is proposed for the development of bio-based plastic materials (bioplastics) as a possible solution to the pollution produced [...] Read more.

The seaweed Rugulopteryx okamurae, from the Pacific Ocean, is considered an invasive species in the Mediterranean Sea. In this work, the use of this seaweed is proposed for the development of bio-based plastic materials (bioplastics) as a possible solution to the pollution produced by the plastic industry. The raw seaweed Rugulopteryx okamurae was firstly blended with glycerol (ratios: 50/50, 60/40 and 70/30), and subsequently, they were processed by injection molding at a mold temperature of 90, 120 and 150 °C. The rheological properties (frequency sweep tests and temperature ramp tests) were obtained for blends before and after processing by injection molding. The functional properties of the bioplastics were determined by the water uptake capacity (WUC) values and further scanning electron microscopy (SEM). The results obtained indicated that E’ was always greater than E”, which implies a predominantly elastic behavior. The 70/30 ratio presents higher values for both the viscoelastic moduli and tensile properties than the rest of the systems (186.53 ± 22.80 MPa and 2.61 ± 0.51 MPa, respectively). The WUC decreased with the increase in seaweed in the mixture, ranging from 262% for the 50/50 ratio to 181% for the 70/30 ratio. When carrying out the study on molded bioplastic 70/30 at different temperatures, the seaweed content did not exert a remarkable influence on the final properties of the bioplastics obtained. Thus, this invasive species could be used as raw material for the manufacture of environmentally friendly materials processed by injection molding, with several applications such as food packaging, control–release, etc. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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14 pages, 4419 KiB

Open AccessArticle

Electrical Impedance of Surface Modified Porous Titanium Implants with Femtosecond Laser

by Paula Navarro, Alberto Olmo, Mercè Giner, Marleny Rodríguez-Albelo, Ángel Rodríguez and Yadir Torres

Materials 2022, 15(2), 461; https://doi.org/10.3390/ma15020461 - 8 Jan 2022

Cited by 6 | Viewed by 1933

Abstract

The chemical composition and surface topography of titanium implants are essential to improve implant osseointegration. The present work studies a non-invasive alternative of electrical impedance spectroscopy for the characterization of the macroporosity inherent to the manufacturing process and the effect of the surface [...] Read more.

The chemical composition and surface topography of titanium implants are essential to improve implant osseointegration. The present work studies a non-invasive alternative of electrical impedance spectroscopy for the characterization of the macroporosity inherent to the manufacturing process and the effect of the surface treatment with femtosecond laser of titanium discs. Osteoblasts cell culture growths on the titanium surfaces of the laser-treated discs were also studied with this method. The measurements obtained showed that the femtosecond laser treatment of the samples and cell culture produced a significant increase (around 50%) in the absolute value of the electrical impedance module, which could be characterized in a wide range of frequencies (being more relevant at 500 MHz). Results have revealed the potential of this measurement technique, in terms of advantages, in comparison to tiresome and expensive techniques, allowing semi-quantitatively relating impedance measurements to porosity content, as well as detecting the effect of surface modification, generated by laser treatment and cell culture. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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Optical and SEM images of some of the samples studied, before and after FS. All optical images are on the same scale, 3:1 (mm). FD: fully dense sample; 30 vol. %: sample with 30% porosity volume. Full article ">Figure 1 Cont.
Optical and SEM images of some of the samples studied, before and after FS. All optical images are on the same scale, 3:1 (mm). FD: fully dense sample; 30 vol. %: sample with 30% porosity volume. Full article ">Figure 2
(a) impedance analyzer used (Hewlett–Packard 4395A). (b) placement of the sample in the HP 16,092 module. (c) measurement circuit used by the impedance analyzer, where the source signal is output from RF OUT port. Vv voltmeter is R port receiver that measures a voltage. Vi voltmeter is A port receiver that measures a voltage of Ro to obtain a current. Full article ">Figure 3
Graphs obtained with the modulus and phase impedance of titanium samples, with 30% and 60% porosity volume. (a) sample with 30% porosity volume before FS, (b) sample with 60% porosity volume before FS, (c) sample with 30% porosity volume after FS, and (d) sample with 60% porosity volume after FS. Full article ">Figure 4
Impedance of the different samples with pore size 100–200 μm (a) before FS, And (b) after FS. The impedance values are directly proportional to the frequency, with higher sensitivities at higher frequencies. (c) Impedance values vs porosity volumes at 250 MHz. Full article ">Figure 5
Percentage relative cell proliferation in MC3T3–E1 cultures after femtosecond laser treatment (by AlamarBlue). Results are represented vs fully dense growth. Significance level at p value < 0.05 (*). Full article ">Figure 6
SEM Image of a samples of porous titanium after the femtosecond surface treatment in-vitro culture (observe the presence of adhered osteoblasts). (A) Fully-dense; (B) 30 vol. % (100–200 µm). Full article ">Figure 7
(a) Impedance values of discs with cell cultures (CC) vs previous impedance values before FS and after FS in fully dense sample. (b) impedance values in 30% porosity volume sample. Full article ">

27 pages, 5516 KiB

Open AccessArticle

ASDesign: A User-Centered Method for the Design of Assistive Technology That Helps Children with Autism Spectrum Disorders Be More Independent in Their Daily Routines

by Raquel Cañete and M. Estela Peralta

Sustainability 2022, 14(1), 516; https://doi.org/10.3390/su14010516 - 4 Jan 2022

Cited by 6 | Viewed by 5095

Abstract

COVID-19 has posed new physical and mental challenges for the population worldwide, establishing social and structural changes in the labor market that could be maintained and implemented permanently. This new reality will require new strategies to improve family and work conciliation, which is [...] Read more.

COVID-19 has posed new physical and mental challenges for the population worldwide, establishing social and structural changes in the labor market that could be maintained and implemented permanently. This new reality will require new strategies to improve family and work conciliation, which is especially challenging for families with children suffering from psychological pathologies such as autism spectrum disorder (ASD). These changes have led to more frequent and intense behavioral problems, causing stress, anxiety, and confusion for these children and their families. Thus, the need to have tools that help parents reconcile work with the care of these children, who have low autonomy, is reinforced. This work develops a method for the design of assistive technology and smart products to support children with ASD in following a routine and managing tasks autonomously. In this way, the article analyzes the design problem including the needs and preferences of children with ASD and their parents during confinement in terms of dependence and adaptability; develops a design method for interactive and smart products focused on children with ASD in confinement situations; and validates this method in a case study, in which a robot is developed that makes it easier for children with ASD to follow a routine. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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14 pages, 2435 KiB

Open AccessArticle

Rice Bran-Based Bioplastics: Effects of Biopolymer Fractions on Their Mechanical, Functional and Microstructural Properties

by María Alonso-González, Manuel Felix and Alberto Romero

Polymers 2022, 14(1), 100; https://doi.org/10.3390/polym14010100 - 28 Dec 2021

Cited by 11 | Viewed by 3602

Abstract

Rice bran is an underutilized by-product of rice production, containing proteins, lipids and carbohydrates (mainly starches). Proteins and starches have been previously used to produce rice bran-based bioplastics, providing a high-added-value by-product, while contributing to the development of biobased, biodegradable bioplastics. However, rice [...] Read more.

Rice bran is an underutilized by-product of rice production, containing proteins, lipids and carbohydrates (mainly starches). Proteins and starches have been previously used to produce rice bran-based bioplastics, providing a high-added-value by-product, while contributing to the development of biobased, biodegradable bioplastics. However, rice bran contains oil (18–22%), which can have a detrimental effect on bioplastic properties. Its extraction could be convenient, since rice bran oil is becoming increasingly attractive due to its variety of applications in the food, pharmacy and cosmetic industries. In this way, the aim of this work was to analyze the effect of the different components of rice bran on the final properties of the bioplastics. Rice bran refining was carried out by extracting the oil and fiber fractions, and the effects of these two procedures on the final properties were addressed with mechanical, functional and microstructural measures. Results revealed that defatted rice bran produced bioplastics with higher viscoelastic moduli and better tensile behavior while decreasing the water uptake capacity and the soluble matter loss of the samples. However, no significant improvements were observed for systems produced from fiber-free rice bran. The microstructures observed in the SEM micrographs matched the obtained results, supporting the conclusions drawn. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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17 pages, 6721 KiB

Open AccessArticle

Effect of the Processing Parameters on the Porosity and Mechanical Behavior of Titanium Samples with Bimodal Microstructure Produced via Hot Pressing

by Ricardo Chávez-Vásconez, Sheila Lascano, Sergio Sauceda, Mauricio Reyes-Valenzuela, Christopher Salvo, Ramalinga Viswanathan Mangalaraja, Francisco José Gotor, Cristina Arévalo and Yadir Torres

Materials 2022, 15(1), 136; https://doi.org/10.3390/ma15010136 - 25 Dec 2021

Cited by 10 | Viewed by 3198

Abstract

Commercially pure (c.p.) titanium grade IV with a bimodal microstructure is a promising material for biomedical implants. The influence of the processing parameters on the physical, microstructural, and mechanical properties was investigated. The bimodal microstructure was achieved from the blends of powder particles [...] Read more.

Commercially pure (c.p.) titanium grade IV with a bimodal microstructure is a promising material for biomedical implants. The influence of the processing parameters on the physical, microstructural, and mechanical properties was investigated. The bimodal microstructure was achieved from the blends of powder particles with different sizes, while the porous structure was obtained using the space-holder technique (50 vol.% of ammonium bicarbonate). Mechanically milled powders (10 and 20 h) were mixed in 50 wt.% or 75 wt.% with c.p. titanium. Four different mixtures of powders were precompacted via uniaxial cold pressing at 400 MPa. Then, the specimens were sintered at 750 °C via hot pressing in an argon gas atmosphere. The presence of a bimodal microstructure, comprised of small-grain regions separated by coarse-grain ones, was confirmed by optical and scanning electron microscopies. The samples with a bimodal microstructure exhibited an increase in the porosity compared with the commercially available pure Ti. In addition, the hardness was increased while the Young’s modulus was decreased in the specimens with 75 wt.% of the milled powders (20 h). Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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SEM images of: (a) as-received titanium powders; (b) NH4HCO3 particles; (c) Ti10 milled powder; (d) Ti20 milled powder. Particle size distribution of: (e) as-received titanium powder; (f) NH4HCO3 particles; (g) Ti10 milled powder; (h) Ti20 milled powder. Full article ">Figure 2
XRD patterns of titanium powders: as-received (black), Ti10 (blue), and Ti20 (red). Full article ">Figure 3
Optical micrographs of Ti samples: (a) c.p. Ti; (b) Ti10–50; (c) Ti20–50; (d) Ti10–75; (e) Ti20–75; BSE-SEM images of Ti foams: (f) c.p. Ti; (g) Ti10–50; (h) Ti20–50; (i) Ti10–75; (j) Ti20–75. Full article ">Figure 3 Cont.
Optical micrographs of Ti samples: (a) c.p. Ti; (b) Ti10–50; (c) Ti20–50; (d) Ti10–75; (e) Ti20–75; BSE-SEM images of Ti foams: (f) c.p. Ti; (g) Ti10–50; (h) Ti20–50; (i) Ti10–75; (j) Ti20–75. Full article ">Figure 4
Microstructural aspects of synthesized Ti20–75 specimen: BSE-SEM images (a) general view of bimodal microstructure; (b) characteristic microstructure of sample with three zones: Zone A—fine particles; Zone B—coarse particle; Zone C—mixed zone. SE-SEM images (c) Macro-pore surface; (d) Micro-pore surface; (e) EDS analysis for the different zones present in bimodal structure: Zone A, Zone B, and Zone C. Full article ">Figure 5
Pore size distribution: (a) Ti10–50, Ti20–50 (50% milled powder); (b) Ti10–75, Ti20–75 (75% milled powder). Full article ">Figure 6
Vickers microhardness distribution for samples: (a) Ti10–50; (b) Ti10–75; (c) Ti20–50; (d) Ti20–75. Full article ">

11 pages, 833 KiB

Open AccessArticle

Occurrence of Linear Alkylbenzene Sulfonates, Nonylphenol Ethoxylates and Di(2-ethylhexyl)phthalate in Composting Processes: Environmental Risks

by Julia Martín, Carmen Mejías, Marina Arenas, Juan Luis Santos, Irene Aparicio and Esteban Alonso

Sustainability 2022, 14(1), 186; https://doi.org/10.3390/su14010186 - 24 Dec 2021

Cited by 2 | Viewed by 2665

Abstract

Composting is an important waste management strategy, providing an economical and environment-friendly approach to sanitizing and stabilizing biosolids for land soil amendment. However, the resulting product can contain a large number of organic pollutants that may have adverse effects on the ecosystem. This [...] Read more.

Composting is an important waste management strategy, providing an economical and environment-friendly approach to sanitizing and stabilizing biosolids for land soil amendment. However, the resulting product can contain a large number of organic pollutants that may have adverse effects on the ecosystem. This paper presents the occurrence of eight widely used organic pollutants (four linear alkylbenzene sulfonates (LAS C10-C13), nonylphenol and its mono- and di-ethoxylates (NPE) and a di(2-ethylhexyl)phthalate (DEHP)) in full-scale composting processes. LAS homologues were detected at the highest concentrations (range of ∑LAS: 2068–9375 mg kg⁻¹ dm), exceeding the limit fixed in the EU Directive draft. The concentration levels of the NPE and DEHP were significantly lower (up to 27.5 and 156.8 mg kg⁻¹ dm, respectively) and did not exceed their fixed limits in the EU Directive draft. Ecotoxicological risk assessment for when compost is amended onto soils has also been evaluated. The concentrations measured represented a medium-low risk for most compounds, although it was not enough in the case of LAS C11 and C13 and NP. Full article

(This article belongs to the Topic Scientific Advances in STEM: Synergies to Achieve Success, 2nd Volume)

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