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Appl. Sci., Volume 10, Issue 19 (October-1 2020) – 383 articles

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Cover Story (view full-size image) Biotoxins in aquatic environments impact human and animal health globally. There are many toxin [...] Read more.
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Open AccessFeature PaperArticle
High Performance Zinc Oxide Nanorod-Doped Ion Imprinted Polypyrrole for the Selective Electrosensing of Mercury II Ions
Appl. Sci. 2020, 10(19), 7010; https://doi.org/10.3390/app10197010 - 08 Oct 2020
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Abstract
A biomimetic, ion-imprinted polymer (IIP) was prepared by electropolymerization of pyrrole at the surface of gold electrodes decorated with vertically grown ZnO nanorods. The vertical growth of the nanorods was achieved via an ultrathin aryl monolayer grafted by reduction of diazonium salt precursor. [...] Read more.
A biomimetic, ion-imprinted polymer (IIP) was prepared by electropolymerization of pyrrole at the surface of gold electrodes decorated with vertically grown ZnO nanorods. The vertical growth of the nanorods was achieved via an ultrathin aryl monolayer grafted by reduction of diazonium salt precursor. Pyrrole was polymerized in the presence of L-cysteine as chelating agent and Hg2+ (template). Hg2+-imprinted polypyrrole (PPy) was also prepared on a bare gold electrode in order to compare the two methods of sensor design (Au-ZnO-IIP vs. Au-IIP). Non-imprinted PPy was prepared in the same conditions but in the absence of any Hg2+ template. The strategy combining diazonium salt modification and ZnO nanorod decoration of gold electrodes permitted us to increase considerably the specific surface area and thus improve the sensor performance. The limit of detection (LOD) of the designed sensor was ~1 pM, the lowest value ever reported in the literature for gold electrode sensors. The dissociation constants between PPy and Hg2+ were estimated at [Kd1 = (7.89 ± 3.63) mM and Kd2 = (38.10 ± 9.22) pM]. The sensitivity of the designed sensor was found to be 0.692 ± 0.034 μA.pM-1. The Au-ZnO-IIP was found to be highly selective towards Hg2+ compared to cadmium, lead and copper ions. This sensor design strategy could open up new horizons in monitoring toxic heavy metal ions in water and therefore contribute to enhancing environmental quality. Full article
(This article belongs to the Special Issue Biomimetic Sensors and Actuators)
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Open AccessArticle
Intelligent Detection of IoT Botnets Using Machine Learning and Deep Learning
Appl. Sci. 2020, 10(19), 7009; https://doi.org/10.3390/app10197009 - 08 Oct 2020
Viewed by 445
Abstract
As the number of Internet of Things (IoT) devices connected to the network rapidly increases, network attacks such as flooding and Denial of Service (DoS) are also increasing. These attacks cause network disruption and denial of service to IoT devices. However, a large [...] Read more.
As the number of Internet of Things (IoT) devices connected to the network rapidly increases, network attacks such as flooding and Denial of Service (DoS) are also increasing. These attacks cause network disruption and denial of service to IoT devices. However, a large number of heterogenous devices deployed in the IoT environment make it difficult to detect IoT attacks using traditional rule-based security solutions. It is challenging to develop optimal security models for each type of the device. Machine learning (ML) is an alternative technique that allows one to develop optimal security models based on empirical data from each device. We employ the ML technique for IoT attack detection. We focus on botnet attacks targeting various IoT devices and develop ML-based models for each type of device. We use the N-BaIoT dataset generated by injecting botnet attacks (Bashlite and Mirai) into various types of IoT devices, including a Doorbell, Baby Monitor, Security Camera, and Webcam. We develop a botnet detection model for each device using numerous ML models, including deep learning (DL) models. We then analyze the effective models with a high detection F1-score by carrying out multiclass classification, as well as binary classification, for each model. Full article
(This article belongs to the Special Issue Cybersecurity)
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Open AccessArticle
Experimental Study and Damage Model on the Seismic Behavior of Reinforced Concrete L-Shaped Columns under Combined Torsion
Appl. Sci. 2020, 10(19), 7008; https://doi.org/10.3390/app10197008 - 08 Oct 2020
Viewed by 297
Abstract
Due to the advantage of saving indoor space, a special-shaped column frame attracted more attention of the engineers and researchers. This paper presented a quasi-static cyclic loading experiment of six specimens of reinforced concrete (RC) L-shaped columns under compression-flexure-shear-torsion combined loadings to investigate [...] Read more.
Due to the advantage of saving indoor space, a special-shaped column frame attracted more attention of the engineers and researchers. This paper presented a quasi-static cyclic loading experiment of six specimens of reinforced concrete (RC) L-shaped columns under compression-flexure-shear-torsion combined loadings to investigate the effect in the ratio of torsion to moment (T/M) and axial compression ratio (n) on their seismic performance. The results showed that the failure modes of L-shaped specimens included bending failure, bending-torsion failure, and torsion-shear failure with the hysteretic curves exhibiting S shape. With the increase of T/M ratio, cracks on the flange developed more fully, and the height of plastic hinge decreased and torsion bearing capacity improved. Besides, as the T/M ratio increased the twist ductility increased, while displacement ductility decreased. On the other hand, with a higher axial compression ratio, torsion bearing capacity and bending stiffness were both increased. Moreover, the equivalent viscous damping coefficient of bending and torsion were 0.08~0.28 and 0.13~0.23, respectively. The average inter-story drift ratio met the requirements of the Chinese standard. Finally, two modified models were proposed to predict the progression of damage for the L-shaped column under combined loading including torsion. Full article
(This article belongs to the Section Civil Engineering)
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Open AccessArticle
Environmental Impacts Associated to Different Stages Spanning from Harvesting to Industrialization of Pineapple through Life Cycle Assessment
Appl. Sci. 2020, 10(19), 7007; https://doi.org/10.3390/app10197007 - 08 Oct 2020
Viewed by 321
Abstract
In this research, environmental impacts associated with the harvest and processing of pineapple (fresh-packed, in syrup, and dehydrated) were determined using the life cycle assessment (LCA) tool and specialized software SimaPro® (version 8.4), according to ISO14040:2006 and ISO14044:2006 standards. The information used [...] Read more.
In this research, environmental impacts associated with the harvest and processing of pineapple (fresh-packed, in syrup, and dehydrated) were determined using the life cycle assessment (LCA) tool and specialized software SimaPro® (version 8.4), according to ISO14040:2006 and ISO14044:2006 standards. The information used to develop inventory included field interviews and industrial visits within the study area. The functional unit was defined as one kilogram of fruit. The selected impact categories were carbon footprint, water footprint, and energy footprint; the results obtained for the agronomic stage were 0.47 kg CO2 eq (equivalent), 78 L of water, and 9.09 MJ, respectively. The growth stage of the pineapple plant was found to be the one that generates greatest environmental impacts for all three categories. For packaged fruit, 0.58 kg CO2 eq, 82 L of water, and 11.03 MJ were quantified; for pineapples in syrup it was 1.12 kg CO2 eq, 103 L of water, and 19.28 MJ; and for dehydrated fruit, it was 5.12 kg CO2 eq, 782 L of water and 97.04 MJ. This concludes that the most significant environmental impact occurred in all cases during the pineapple cultivation stage. Full article
(This article belongs to the Section Environmental and Sustainable Science and Technology)
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Open AccessCase Report
Robust Optimization Approaches for a Natural Pharmaceutical Complex Product of Atractylodes Japonica Koidz and Schisandra Chinensis
Appl. Sci. 2020, 10(19), 7006; https://doi.org/10.3390/app10197006 - 08 Oct 2020
Viewed by 289
Abstract
Experimental results pertaining to natural pharmaceutical complex products (NPCPs) often exhibit large variabilities in their associated response variables. To improve the quality of an NPCP, systemic studies (i.e., statistical analysis and mathematical optimization), including variability analysis and robust optimization, are often required. To [...] Read more.
Experimental results pertaining to natural pharmaceutical complex products (NPCPs) often exhibit large variabilities in their associated response variables. To improve the quality of an NPCP, systemic studies (i.e., statistical analysis and mathematical optimization), including variability analysis and robust optimization, are often required. To this end, a systemic approach for an NPCP development process is proposed by integrating robust design and optimization methodologies. A quality function deployment method can be used to systematically define a standardized manufacturing process and relevant process variables for Chong Kun Dang (CKD)-497. Based on those variables, an experiment is designed using response surface methodology to mathematically estimate the output response functions associated with input variables. In addition, a design space (DS), which can guarantee the quality of an NPCP, is demonstrated by utilizing the overlaid contour plots of the estimated response functions. Finally, a CKD-497 case study is conducted for verification and validation. Full article
(This article belongs to the Section Applied Industrial Technologies)
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Open AccessArticle
Development and Application of a Human–Machine Interface Using Head Control and Flexible Numeric Tables for the Severely Disabled
Appl. Sci. 2020, 10(19), 7005; https://doi.org/10.3390/app10197005 - 08 Oct 2020
Viewed by 284
Abstract
The human–machine interface with head control can be applied in many domains. This technology has the valuable application of helping people who cannot use their hands, enabling them to use a computer or speak. This study combines several image processing and computer vision [...] Read more.
The human–machine interface with head control can be applied in many domains. This technology has the valuable application of helping people who cannot use their hands, enabling them to use a computer or speak. This study combines several image processing and computer vision technologies, a digital camera, and software to develop the following system: image processing technologies are adopted to capture the features of head motion; the recognized head gestures include forward, upward, downward, leftward, rightward, right-upper, right-lower, left-upper, and left-lower; corresponding sound modules are used so that patients can communicate with others through a phonetic system and numeric tables. Innovative skin color recognition technology can obtain head features in images. The barycenter of pixels in the feature area is then quickly calculated, and the offset of the barycenter is observed to judge the direction of head motion. This architecture can substantially reduce the distraction of non-targeted objects and enhance the accuracy of systematic judgment. Full article
(This article belongs to the Special Issue Nonlinear Control: Theory and Applications)
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Open AccessArticle
A 3-D Simulation of a Single-Sided Linear Induction Motor with Transverse and Longitudinal Magnetic Flux
Appl. Sci. 2020, 10(19), 7004; https://doi.org/10.3390/app10197004 - 08 Oct 2020
Viewed by 286
Abstract
This paper presents a novel and improved configuration of a single-sided linear induction motor. The geometry of the motor has been modified to be able to operate with a mixed magnetic flux configuration and with a new configuration of paths for the eddy [...] Read more.
This paper presents a novel and improved configuration of a single-sided linear induction motor. The geometry of the motor has been modified to be able to operate with a mixed magnetic flux configuration and with a new configuration of paths for the eddy currents induced inside the aluminum plate. To this end, two slots of dielectric have been introduced into the aluminum layer of the moving part with a dimension of 1 mm, an iron yoke into the primary part, and lastly, the width of the transversal slots has been optimized. Specifically, in the enhanced motor, there are two magnetic fluxes inside the motor that circulate across two different planes: a longitudinal magnetic flux which goes along the direction of the movement and a transversal magnetic flux which is closed through a perpendicular plane with respect to that direction. With this new configuration, the motor achieves a great increment of the thrust force without increasing the electrical supply. In addition, the proposed model creates a new spatial configuration of the eddy currents and an improvement of the main magnetic circuit. These novelties are relevant because they represent a great improvement in the efficiency of the linear induction motor for low velocities at a very low cost. All simulations have been made with the finite elements method—3D, both in standstill conditions and in motion in order to obtain the characteristic curves of the main forces developed by the linear induction motor. Full article
(This article belongs to the Special Issue Modeling, Design and Control of Electric Machines)
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Open AccessArticle
Synthesis of Normal Heart Sounds Using Generative Adversarial Networks and Empirical Wavelet Transform
Appl. Sci. 2020, 10(19), 7003; https://doi.org/10.3390/app10197003 - 08 Oct 2020
Viewed by 293
Abstract
Currently, there are many works in the literature focused on the analysis of heart sounds, specifically on the development of intelligent systems for the classification of normal and abnormal heart sounds. However, the available heart sound databases are not yet large enough to [...] Read more.
Currently, there are many works in the literature focused on the analysis of heart sounds, specifically on the development of intelligent systems for the classification of normal and abnormal heart sounds. However, the available heart sound databases are not yet large enough to train generalized machine learning models. Therefore, there is interest in the development of algorithms capable of generating heart sounds that could augment current databases. In this article, we propose a model based on generative adversary networks (GANs) to generate normal synthetic heart sounds. Additionally, a denoising algorithm is implemented using the empirical wavelet transform (EWT), allowing a decrease in the number of epochs and the computational cost that the GAN model requires. A distortion metric (mel–cepstral distortion) was used to objectively assess the quality of synthetic heart sounds. The proposed method was favorably compared with a mathematical model that is based on the morphology of the phonocardiography (PCG) signal published as the state of the art. Additionally, different heart sound classification models proposed as state-of-the-art were also used to test the performance of such models when the GAN-generated synthetic signals were used as test dataset. In this experiment, good accuracy results were obtained with most of the implemented models, suggesting that the GAN-generated sounds correctly capture the characteristics of natural heart sounds. Full article
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Open AccessArticle
Optimization of the Antioxidant Activities of Mixtures of Melastomataceae Leaves Species (M. malabathricum Linn Smith, M. decemfidum, and M. hirta) Using a Simplex Centroid Design and Their Anti-Collagenase and Elastase Properties
Appl. Sci. 2020, 10(19), 7002; https://doi.org/10.3390/app10197002 - 08 Oct 2020
Viewed by 263
Abstract
In this study, a simplex-centroid mixture design (SCMD) approach was used to select the optimal proportions of three different Melastomataceae leaves species (M. malabathricum, M. decemfidum, and M. hirta) extracts to determine the optimum antioxidant activities of total phenolic [...] Read more.
In this study, a simplex-centroid mixture design (SCMD) approach was used to select the optimal proportions of three different Melastomataceae leaves species (M. malabathricum, M. decemfidum, and M. hirta) extracts to determine the optimum antioxidant activities of total phenolic compound (TPC) and ABTS (2, 2′-azino-bis (ethylbenzthiazoline-6-sulfonic acid)) radical-scavenging activities. Twelve experimental designs were set up, consisting of points that were equally weighted mixtures of 0 to 1 components, which were pure blends (1, 0, …, 0), binary blends (1/2, 1/2, 0, …, 0), tertiary blends (1/3, 1/3, 1/3, 0, …, 0), and a control point. The in vitro anti-elastase and collagenase activities were evaluated in order to determine the anti-aging efficacy of the optimized mixture extracts. A high-performance liquid chromatography (HPLC) analysis was employed to identify the flavonoid content (rutin and quercetin) present in the optimized mixture extracts. The results showed that the best proportions of the optimum phenolic compounds and ABTS activity corresponded to 30%, 40%, and 30% of M. malabathricum, M. hirta, and M. decemfidum leaf extracts, respectively. The in vitro anti-collagenase and elastase activity evaluation of the optimized mixture extracts showed 70% inhibition against both elastase and collagenase enzymes. The HPLC analysis revealed two flavonoids (rutin and quercetin) at retention time 7.770 and 8.769 min, respectively, in the mixture extracts. This study suggests the potential exploitation of mixtures of Melastomataceae leaves (M. malabathricum, M. decemfidum, and M. hirta) as cosmetic ingredients for antioxidant and anti-wrinkles applications. Full article
(This article belongs to the Section Chemistry)
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Open AccessArticle
Characterization of Gait and Postural Regulation in Late-Onset Pompe Disease
Appl. Sci. 2020, 10(19), 7001; https://doi.org/10.3390/app10197001 - 08 Oct 2020
Viewed by 303
Abstract
Pompe disease is a multisystemic disorder with the hallmark of progressive skeletal muscle weakness that often results in difficulties in walking and balance. However, detailed characterization of gait and postural regulation with this disease is lacking. The objective of this investigation was to [...] Read more.
Pompe disease is a multisystemic disorder with the hallmark of progressive skeletal muscle weakness that often results in difficulties in walking and balance. However, detailed characterization of gait and postural regulation with this disease is lacking. The objective of this investigation was to determine if differences exist between the gait and postural regulation of LOPD patients and a matched control group. The gaits of 16 patients with LOPD were assessed using a gait analysis mobile system (RehaGait) and a dynamometric treadmill (FDM-T 1.8). The Interactive Balance System (IBS) was used to evaluate postural regulation and stability. All measures were compared to individual reference data. Demographic (age, gender), morphological (body height, body mass) and clinical data (muscle strength according to the Medical Research Council Scale (MRC Scale), as well as the 6-min walking test and a 10-m fast walk) were also recorded. Compared to individual reference data, LOPD patients presented with reduced gait velocity, cadence and time in single stand. A total of 87% of LOPD patients had abnormalities during posturographic analysis presenting with differences in postural subsystems. This study provides objective data demonstrating impaired gait and posture in LOPD patients. For follow-up analysis and as outcome measurements during medical or physiotherapeutic interventions, the findings of this investigation may be useful. Full article
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Open AccessArticle
Quantum-Based Analytical Techniques on the Tackling of Well Placement Optimization
Appl. Sci. 2020, 10(19), 7000; https://doi.org/10.3390/app10197000 - 08 Oct 2020
Viewed by 345
Abstract
The high dimensional, multimodal, and discontinuous well placement optimization is one of the main difficult factors in the development process of conventional as well as shale gas reservoir, and to optimize this problem, metaheuristic techniques still suffer from premature convergence. Hence, to tackle [...] Read more.
The high dimensional, multimodal, and discontinuous well placement optimization is one of the main difficult factors in the development process of conventional as well as shale gas reservoir, and to optimize this problem, metaheuristic techniques still suffer from premature convergence. Hence, to tackle this problem, this study aims at introducing a dimension-wise diversity analysis for well placement optimization. Moreover, in this article, quantum computational techniques are proposed to tackle the well placement optimization problem. Diversity analysis reveals that dynamic exploration and exploitation strategy is required for each reservoir. In case studies, the results of the proposed approach outperformed all the state-of-the-art algorithms and provided a better solution than other algorithms with higher convergence rate, efficiency, and effectiveness. Furthermore, statistical analysis shows that there is no statistical difference between the performance of Quantum bat algorithm and Quantum Particle swarm optimization algorithm. Hence, this quantum adaptation is the main factor that enhances the results of the optimization algorithm and the approach can be applied to locate wells in conventional and shale gas reservoir. Full article
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Open AccessArticle
Prosody-Based Measures for Automatic Severity Assessment of Dysarthric Speech
Appl. Sci. 2020, 10(19), 6999; https://doi.org/10.3390/app10196999 - 08 Oct 2020
Viewed by 337
Abstract
One of the first cues for many neurological disorders are impairments in speech. The traditional method of diagnosing speech disorders such as dysarthria involves a perceptual evaluation from a trained speech therapist. However, this approach is known to be difficult to use for [...] Read more.
One of the first cues for many neurological disorders are impairments in speech. The traditional method of diagnosing speech disorders such as dysarthria involves a perceptual evaluation from a trained speech therapist. However, this approach is known to be difficult to use for assessing speech impairments due to the subjective nature of the task. As prosodic impairments are one of the earliest cues of dysarthria, the current study presents an automatic method of assessing dysarthria in a range of severity levels using prosody-based measures. We extract prosodic measures related to pitch, speech rate, and rhythm from speakers with dysarthria and healthy controls in English and Korean datasets, despite the fact that these two languages differ in terms of prosodic characteristics. These prosody-based measures are then used as inputs to random forest, support vector machine and neural network classifiers to automatically assess different severity levels of dysarthria. Compared to baseline MFCC features, 18.13% and 11.22% relative accuracy improvement are achieved for English and Korean datasets, respectively, when including prosody-based features. Furthermore, most improvements are obtained with a better classification of mild dysarthric utterances: a recall improvement from 42.42% to 83.34% for English speakers with mild dysarthria and a recall improvement from 36.73% to 80.00% for Korean speakers with mild dysarthria. Full article
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Open AccessArticle
Comparison of Physicochemical, Functional and Nutritional Properties between Proteins of Soybean and a Novel Mixture of Soybean-Maize
Appl. Sci. 2020, 10(19), 6998; https://doi.org/10.3390/app10196998 - 08 Oct 2020
Viewed by 371
Abstract
Vegetable proteins are potential low-cost alternatives to solve the protein deficiency of the world population. A protein extracted from a mixture of soybean meal and maize germ was developed to offer more protein alternatives with high nutritional value. In this study, physicochemical, functional, [...] Read more.
Vegetable proteins are potential low-cost alternatives to solve the protein deficiency of the world population. A protein extracted from a mixture of soybean meal and maize germ was developed to offer more protein alternatives with high nutritional value. In this study, physicochemical, functional, and nutritional characteristics of isolates and hydrolysates of soybean and counterparts extracted from a soybean meal-maize germ were compared. The isolate and hydrolysate of the soybean-maize blend had a protein content of 93.9% and 73.6%, respectively. These protein mixtures contained 10% and 52% more solubility, 303.9%, and 22.7% more emulsifying capacity, 4.5% and 4.2% higher foam density and 36.3% and 1.2% more coagulation capacity compared to the soybean isolate and hydrolysate. Electrophoretic profiles of soybean-maize proteins showed four additional bands to the typical soybean pattern of 56, 55, 52 and 18 kDa, which could correspond to globulins and zeins from maize. The isolate extracted from the mixture of soybean meal and maize is a new alternative to provide the necessary amino acids for proper physical and mental development. Additionally, it has a high potential to be used as an ingredient by the food industry due to its excellent functionality and nutritional value. Full article
(This article belongs to the Section Food Science and Technology)
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Open AccessArticle
Deep Learning for Traffic Sign Recognition Based on Spatial Pyramid Pooling with Scale Analysis
Appl. Sci. 2020, 10(19), 6997; https://doi.org/10.3390/app10196997 - 07 Oct 2020
Viewed by 438
Abstract
In the area of traffic sign detection (TSD) methods, deep learning has been implemented and achieves outstanding performance. The detection of a traffic sign, as it has a dual function in monitoring and directing the driver, is a big concern for driver support [...] Read more.
In the area of traffic sign detection (TSD) methods, deep learning has been implemented and achieves outstanding performance. The detection of a traffic sign, as it has a dual function in monitoring and directing the driver, is a big concern for driver support systems. A core feature of autonomous vehicle systems is the identification of the traffic sign. This article focuses on the prohibitive sign. The objective is to detect in real-time and reduce processing time considerably. In this study, we implement the spatial pyramid pooling (SPP) principle to boost Yolo V3’s backbone network for the extraction of functionality. Our work uses SPP for more comprehensive learning of multiscale object features. Then, perform a comparative investigation of Yolo V3 and Yolo V3 SPP across various scales to recognize the prohibitory sign. Comparisons with Yolo V3 SPP models reveal that their mean average precision (mAP) is higher than Yolo V3. Furthermore, the test accuracy findings indicate that the Yolo V3 SPP model performs better than Yolo V3 for different sizes. Full article
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Open AccessArticle
The Invasion of Bacterial Biofilms into the Dentinal Tubules of Extracted Teeth Retrofilled with Fluorescently Labeled Retrograde Filling Materials
Appl. Sci. 2020, 10(19), 6996; https://doi.org/10.3390/app10196996 - 07 Oct 2020
Viewed by 334
Abstract
In this study, we evaluated the invasion of bacteria into the dentinal tubules of retrofilled extracted human teeth, and the influence of different fluorescently labeled retrograde filling materials on the bacterial invasion and viability, by means of confocal laser scanning microscopy (CLSM). The [...] Read more.
In this study, we evaluated the invasion of bacteria into the dentinal tubules of retrofilled extracted human teeth, and the influence of different fluorescently labeled retrograde filling materials on the bacterial invasion and viability, by means of confocal laser scanning microscopy (CLSM). The root apices of extracted teeth were cut, prepared, and filled retrogradely using either intermediate restorative material (IRM), mineral trioxide aggregate (MTA), or Biodentine. The roots were filled with Enterococcus faecalis bacteria from their coronal part for 21 days. Then, 3-mm-long apical segments were cut to get root axial slices, and the bacteria were fluorescently stained and evaluated by CLSM. Bacterial penetration into the dentinal tubules favored the bucco-lingual directions. The filling materials penetrated up to 957 µm into the tubuli, and the bacteria, up to 1480 µm (means: 130 and 167 μm, respectively). Biodentine fillings penetrated less and the associated bacteria penetrated deeper into the tubuli compared to MTA or IRM (p = 0.004). Deeper filling penetration was associated with shallower penetration of both dead and live, or live alone, bacteria (p = 0.015). In conclusion, the current study enables better understanding of the microbiological–pathological course after endodontic surgical procedures. It was found that even with retrograde fillings, bacteria invade deep into the dental tubules, where deeper filling penetration prevents deeper penetration of the bacteria and adversely affects the viability of the bacteria. Full article
(This article belongs to the Special Issue Predictable Restorative Dentistry)
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Open AccessArticle
Fusing Hand Postures and Speech Recognition for Tasks Performed by an Integrated Leg–Arm Hexapod Robot
Appl. Sci. 2020, 10(19), 6995; https://doi.org/10.3390/app10196995 - 07 Oct 2020
Viewed by 269
Abstract
Hand postures and speech are convenient means of communication for humans and can be used in human–robot interaction. Based on structural and functional characteristics of our integrated leg-arm hexapod robot, to perform reconnaissance and rescue tasks in public security application, a method of [...] Read more.
Hand postures and speech are convenient means of communication for humans and can be used in human–robot interaction. Based on structural and functional characteristics of our integrated leg-arm hexapod robot, to perform reconnaissance and rescue tasks in public security application, a method of linkage of movement and manipulation of robots is proposed based on the visual and auditory channels, and a system based on hand postures and speech recognition is described. The developed system contains: a speech module, hand posture module, fusion module, mechanical structure module, control module, path planning module and a 3D SLAM (Simultaneous Localization and Mapping) module. In this system, three modes, i.e., the hand posture mode, speech mode, and a combination of the hand posture and speech modes, are used in different situations. The hand posture mode is used for reconnaissance tasks, and the speech mode is used to query the path and control the movement and manipulation of the robot. The combination of the two modes can be used to avoid ambiguity during interaction. A semantic understanding-based task slot structure is developed by using the visual and auditory channels. In addition, a method of task planning based on answer-set programming is developed, and a system of network-based data interaction is designed to control movements of the robot using Chinese instructions remotely based on a wide area network. Experiments were carried out to verify the performance of the proposed system. Full article
(This article belongs to the Special Issue Novel Approaches and Applications in Ergonomic Design)
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Open AccessArticle
A Ka-Band Circular Polarized Waveguide Slot Antenna with a Cross Iris
Appl. Sci. 2020, 10(19), 6994; https://doi.org/10.3390/app10196994 - 07 Oct 2020
Viewed by 298
Abstract
A Ka-band circularly polarized (CP) waveguide slot antenna with a cross iris is proposed. To achieve the CP characteristic (LHCP) in the antenna, a hexagonal shaped cavity is used. The impedance matching is improved by adjusting the sizes of the hexagonal cavity and [...] Read more.
A Ka-band circularly polarized (CP) waveguide slot antenna with a cross iris is proposed. To achieve the CP characteristic (LHCP) in the antenna, a hexagonal shaped cavity is used. The impedance matching is improved by adjusting the sizes of the hexagonal cavity and a rectangular matching cavity. To enhance the axial ratio bandwidth, a cross iris is used with two arms of different lengths. From experimental results, the proposed antenna has a 3 dB axial ratio bandwidth of 6810 MHz (31.72 GHz–38.53 GHz). The −10 dB reflection coefficient bandwidth of the proposed antenna ranges from 31.51 GHz to 39.21 GHz (7700 MHz). Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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Open AccessArticle
Low Voltage Delay Element with Dynamic Biasing Technique for Fully Integrated Cold-Start in Battery-Assistance DC Energy Harvesting Systems
Appl. Sci. 2020, 10(19), 6993; https://doi.org/10.3390/app10196993 - 07 Oct 2020
Viewed by 167
Abstract
This paper proposes an ultra-low voltage delay element for battery-assistance DC energy harvesting systems. By inserting a low voltage level shifter (VLS), a wider voltage range is obtained to bias the body of the delay element. Thus, both the voltage transfer curve (VTC) [...] Read more.
This paper proposes an ultra-low voltage delay element for battery-assistance DC energy harvesting systems. By inserting a low voltage level shifter (VLS), a wider voltage range is obtained to bias the body of the delay element. Thus, both the voltage transfer curve (VTC) and the DC gain of the delay element are enhanced. Due to the introduction of the VLS, the cold start-up ring oscillator constituted by the proposed delay element can achieve oscillation under an extremely low input voltage. The fully integrated cold start-up ring oscillator with 21 stages of the proposed element is implemented in a standard 180 nm complementary metal oxide semiconductor (CMOS) process. The post-layout experimental results indicate that the cold start-up ring oscillator can retain oscillation when the power supply voltage (VDD) is 24 mV under a typical corner at room temperature. The output voltage swing of the cold start-up ring oscillator based on the proposed delay element is improved by more than 55% under VDD = 40 mV compared with a stacked inverter-based cold start-up ring oscillator. Monte Carlo (MC) simulation from 100 samples shows the enhanced output swing with the proposed delay element under process variation. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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Open AccessArticle
Using Long-Range Wireless Sensor Network to Track the Illegal Cutting Log
Appl. Sci. 2020, 10(19), 6992; https://doi.org/10.3390/app10196992 - 07 Oct 2020
Viewed by 171
Abstract
Nowadays, the need for wireless sensing applications is increasing. Along with the increased illegal cutting of logs in the forest, however, it requires the integration application to tackle the illegal logging and forest preservation. The wireless sensor network is a suitable network architecture [...] Read more.
Nowadays, the need for wireless sensing applications is increasing. Along with the increased illegal cutting of logs in the forest, however, it requires the integration application to tackle the illegal logging and forest preservation. The wireless sensor network is a suitable network architecture for remotely monitoring or tracking applications in the environment. This paper proposed an integrated system that can identify and track the position of a moving cutting log. An Arduino Uno, Raspberry Pi 3 B+, sound sensor, accelerometer sensor, LoRa GPS HAT Shield, and Outdoor LoRa Gateway OLG01 performed the hardware monitoring and tracking of the proposed system. The network of STAR topology configuration between master and slaves is represented by the LoRa Network embedded with the sensors, as an architecture of the wireless sensor network. The system was examined the performance of the network and the tracking process. The result determined that the LoRa can detect and identify the occurrence of the illegal cutting of logs in real-time. Meanwhile, in terms of the tracking performance, a duration of 5–46 s was required to track the new position of the moving cutting log. Full article
(This article belongs to the Section Electrical, Electronics and Communications Engineering)
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Open AccessArticle
Field-Applicable Pig Anomaly Detection System Using Vocalization for Embedded Board Implementations
Appl. Sci. 2020, 10(19), 6991; https://doi.org/10.3390/app10196991 - 07 Oct 2020
Viewed by 185
Abstract
Failure to quickly and accurately detect abnormal situations, such as the occurrence of infectious diseases, in pig farms can cause significant damage to the pig farms and the pig farming industry of the country. In this study, we propose an economical and lightweight [...] Read more.
Failure to quickly and accurately detect abnormal situations, such as the occurrence of infectious diseases, in pig farms can cause significant damage to the pig farms and the pig farming industry of the country. In this study, we propose an economical and lightweight sound-based pig anomaly detection system that can be applicable even in small-scale farms. The system consists of a pipeline structure, starting from sound acquisition to abnormal situation detection, and can be installed and operated in an actual pig farm. It has the following structure that makes it executable on the embedded board TX-2: (1) A module that collects sound signals; (2) A noise-robust preprocessing module that detects sound regions from signals and converts them into spectrograms; and (3) A pig anomaly detection module based on MnasNet, a lightweight deep learning method, to which the 8-bit filter clustering method proposed in this study is applied, reducing its size by 76.3% while maintaining its identification performance. The proposed system recorded an F1-score of 0.947 as a stable pig’s abnormality identification performance, even in various noisy pigpen environments, and the system’s execution time allowed it to perform in real time. Full article
(This article belongs to the Special Issue Deep Learning-Based Smart Farm Techniques)
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Open AccessArticle
Deposition of Copper on Polyester Knitwear Fibers by a Magnetron Sputtering System. Physical Properties and Evaluation of Antimicrobial Response of New Multi-Functional Composite Materials
Appl. Sci. 2020, 10(19), 6990; https://doi.org/10.3390/app10196990 - 07 Oct 2020
Viewed by 194
Abstract
In this study, copper films were deposited by magnetron sputtering on poly(ethylene terephthalate) knitted textile to fabricate multi-functional, antimicrobial composite material. The modified knitted textile composites were subjected to microbial activity tests against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative ( [...] Read more.
In this study, copper films were deposited by magnetron sputtering on poly(ethylene terephthalate) knitted textile to fabricate multi-functional, antimicrobial composite material. The modified knitted textile composites were subjected to microbial activity tests against colonies of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and antifungal tests against Chaetomium globosum fungal molds species. The prepared samples were characterized by UV/VIS transmittance, scanning electron microscopy (SEM), tensile and filtration parameters and the ability to block UV radiation. The performed works proved the possibility of manufacturing a new generation of antimicrobial textile composites with barrier properties against UV radiation, produced by a simple, zero-waste method. The specific advantages of using new poly(ethylene terephthalate)-copper composites are in biomedical applications areas. Full article
(This article belongs to the Section Applied Biosciences and Bioengineering)
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Open AccessFeature PaperArticle
Pulsed Electric Fields (PEF) to Mitigate Emerging Mycotoxins in Juices and Smoothies
Appl. Sci. 2020, 10(19), 6989; https://doi.org/10.3390/app10196989 - 07 Oct 2020
Viewed by 174
Abstract
The development of innovative food processing technologies has increased to answer the growing demand to supply of fresh-like products. The aim of the present study is to investigate the effect of pulsed electric fields (PEF) technology on reducing the emerging mycotoxins (enniatins (ENs) [...] Read more.
The development of innovative food processing technologies has increased to answer the growing demand to supply of fresh-like products. The aim of the present study is to investigate the effect of pulsed electric fields (PEF) technology on reducing the emerging mycotoxins (enniatins (ENs) and beauvericin (BEA)) contents in juice and smoothie samples. The products of degradation obtained after PEF treatment were identified and their toxicological endpoint toxicities predicted by Pro Tox-II web. Mycotoxin reduction ranged from 43 to 70% in juices and smoothies, but in water the expected effect was lower. The acidified pH increased BEA reduction in water. The degradation products that were produced were the result of the loss of aminoacidic fragments of the original molecules, such as HyLv, Val, Ile, or Phe. Pro Tox-II server assigned a toxicity class I for enniatin B (ENB) degradation products with a predicted LD50 of 3 mg/Kgbw. The other degradation products were classified in toxicity class III and IV. Full article
(This article belongs to the Special Issue Mechanism of Action of Toxicants and Food Constituents)
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Open AccessFeature PaperArticle
Impact of High Intensity Interval Training Using Elastic Bands on Glycemic Control in Adults with Type 1 Diabetes: A Pilot Study
Appl. Sci. 2020, 10(19), 6988; https://doi.org/10.3390/app10196988 - 07 Oct 2020
Viewed by 195
Abstract
High intensity interval training (HIIT) using elastic bands is easy to do, but no data on its impact on glycemic control in people with type 1 diabetes (T1D) are available. Six males with T1D performed three weekly sessions of HIIT using elastic bands [...] Read more.
High intensity interval training (HIIT) using elastic bands is easy to do, but no data on its impact on glycemic control in people with type 1 diabetes (T1D) are available. Six males with T1D performed three weekly sessions of HIIT using elastic bands for 12 weeks. Each session consisted of eight exercises. Glycemic control was evaluated by using intermittent scanning continuous glucose monitoring two weeks before study onset (baseline) and during the intervention period in the first two (first stage) and last two weeks (last stage). In the 24 h post-exercise, time-in-range (70–180 mg/dL) was reduced from baseline to the end of the study (67.2% to 63.0%), and time-above-range (>180 mg/dL) seemed to increase from baseline across the study (20.8% → 27.5% → 22.1%, from baselinefirstlast stage), but did not show any statistical significance. Time in hypoglycemia (either < 70 mg/dL or <54 mg/dL) did not show statistically significant differences. This study shows that a HIIT program with elastic bands is safe and effective to perform in T1D patients, keeping blood glucose levels in a safe range. Full article
(This article belongs to the Special Issue Applied Biomechanics in Sport, Rehabilitation and Ergonomy)
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Open AccessArticle
In Vitro Assessment of Antiplasmodial and Antitrypanosomal Activities of Chloroform, Ethyl Acetate and Ethanol Leaf Extracts of Oedera genistifolia
Appl. Sci. 2020, 10(19), 6987; https://doi.org/10.3390/app10196987 - 07 Oct 2020
Viewed by 160
Abstract
The high resistance evolution of protozoans to the existing antiparasitic drugs has necessitated the quest for novel and effective drugs against plasmodium and trypanosome parasites. As a result, this study aimed to assess the antiplasmodial and antitrypanosomal potentials of chloroform, ethyl acetate and [...] Read more.
The high resistance evolution of protozoans to the existing antiparasitic drugs has necessitated the quest for novel and effective drugs against plasmodium and trypanosome parasites. As a result, this study aimed to assess the antiplasmodial and antitrypanosomal potentials of chloroform, ethyl acetate and ethanol leaf extracts of Oedera genistifolia. Standard biochemical procedures were explored for the plant extraction and gas chromatography-mass spectroscopy (GCMS) was used to identify the bioactive compounds in the crude extracts. The cytotoxic effects of the crude extracts were assessed against human cervix adenocarcinoma (HeLa cells) and their antiparasitic activities were investigated against Plasmodium falciparum strain 3D7 and Trypanosoma brucei brucei. GCMS analyses of the crude extracts revealed the bioactive compounds that could be responsible for the biological activities. The extracts had no cytotoxic effect on HeLa cells and demonstrated good antiplasmodial activity (chloroform extract: IC50 = 11.6 µg∙mL−1, ethyl acetate extract: IC50 = 3.3 µg∙mL−1 and ethanol extract: IC50 = 3.7 µg∙mL−1). Likewise, they showed excellent antitrypanosomal activity with IC50 = 0.5 µg∙mL−1 for chloroform and ethyl acetate extracts and IC50 = 0.4 µg∙mL−1 for the ethanol extract. Findings from the present study indicated that O. genistifolia could be a good source of strong antiplasmodial and antitrypanosomal agents. Full article
(This article belongs to the Section Applied Biosciences and Bioengineering)
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Open AccessArticle
Framework for Developing Bio-Inspired Morphologies for Walking Robots
Appl. Sci. 2020, 10(19), 6986; https://doi.org/10.3390/app10196986 - 07 Oct 2020
Viewed by 427
Abstract
Morphology is a defining trait of any walking entity, animal or robot, and is crucial in obtaining movement versatility, dexterity and durability. Collaborations between biologist and engineers create opportunities for implementing bio-inspired morphologies in walking robots. However, there is little guidance for such [...] Read more.
Morphology is a defining trait of any walking entity, animal or robot, and is crucial in obtaining movement versatility, dexterity and durability. Collaborations between biologist and engineers create opportunities for implementing bio-inspired morphologies in walking robots. However, there is little guidance for such interdisciplinary collaborations and what tools to use. We propose a development framework for transferring animal morphologies to robots and substantiate it with a replication of the ability of the dung beetle species Scarabaeus galenus to use the same morphology for both locomotion and object manipulation. As such, we demonstrate the advantages of a bio-inspired dung beetle-like robot, ALPHA, and how its morphology outperforms a conventional hexapod by increasing the (1) step length by 50.0%, (2) forward and upward reach by 95.5%, and by lowering the (3) overall motor acceleration by 7.9%, and (4) step frequency by 21.1% at the same walking speed. Thereby, the bio-inspired robot has longer and fewer steps that lower fatigue-inducing impulses, a greater variety of step patterns, and can potentially better utilise its workspace to overcome obstacles. Hence, we demonstrate how the framework can be used to develop legged robots with bio-inspired morphologies that embody greater movement versatility, dexterity and durability. Full article
(This article belongs to the Special Issue Bio-Inspired Robotics II)
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Open AccessArticle
Compressible Two-Phase Viscous Flow Investigations of Cavitation Dynamics for the ITTC Standard Cavitator
Appl. Sci. 2020, 10(19), 6985; https://doi.org/10.3390/app10196985 - 07 Oct 2020
Viewed by 221
Abstract
In this paper, the ITTC Standard Cavitator is numerically investigated in a cavitation tunnel. Simulations at different cavitation numbers are compared against experiments conducted in the cavitation tunnel of SVA Potsdam. The focus is placed on the numerical prediction of sheet-cavitation dynamics and [...] Read more.
In this paper, the ITTC Standard Cavitator is numerically investigated in a cavitation tunnel. Simulations at different cavitation numbers are compared against experiments conducted in the cavitation tunnel of SVA Potsdam. The focus is placed on the numerical prediction of sheet-cavitation dynamics and the analysis of transient phenomena. A compressible two-phase flow model is used for the flow solution, and two turbulence closures are employed: a two-equation unsteady RANS model, and a hybrid RANS/LES model. A homogeneous mixture model is used for the two phases. Detailed analysis of the cavitation shedding mechanism confirms that the dynamics of the sheet cavitation are dictated by the re-entrant jet. The break-off cycle is relatively periodic in both investigated cases with approximately constant shedding frequency. The CFD predicted sheet-cavitation shedding frequencies can be observed also in the acoustic measurements. The Strouhal numbers lie within the usual ranges reported in the literature for sheet-cavitation shedding. We furthermore demonstrate that the vortical flow structures can in certain cases develop striking cavitating toroidal vortices, as well as pressure wave fronts associated with a cavity cloud collapse event. To our knowledge, our numerical analyses are the first reported for the ITTC standard cavitator. Full article
(This article belongs to the Special Issue New Advances of Cavitation Instabilities)
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Open AccessArticle
Change of Direction Performance Is Influenced by Asymmetries in Jumping Ability and Hip and Trunk Strength in Elite Basketball Players
Appl. Sci. 2020, 10(19), 6984; https://doi.org/10.3390/app10196984 - 06 Oct 2020
Viewed by 305
Abstract
Change of direction (COD) ability is essential for sport performance in high level team sports such as basketball, however, the influence of asymmetries on COD ability is relatively unknown. Forty-three junior and senior level elite basketball players performed isometric hip and trunk strength [...] Read more.
Change of direction (COD) ability is essential for sport performance in high level team sports such as basketball, however, the influence of asymmetries on COD ability is relatively unknown. Forty-three junior and senior level elite basketball players performed isometric hip and trunk strength testing, passive hip and trunk range of motion testing, and unilateral horizontal and vertical jumps, as well as the T-test to measure COD performance. Mean asymmetry values ranged from 0.76% for functional leg length up to 40.35% for rate of torque development during hip flexion. A six-variable regression model explained 48% (R2 = 0.48; p < 0.001) of variation in COD performance. The model included left hip internal/external rotation strength ratio, and inter-limb asymmetries in hip abduction rate of torque development, hip flexion range of motion, functional leg length, single leg triple jump distance, and peak torque during trunk lateral flexion. Results suggest that the magnitude of asymmetries is dependent of task and parameter, and using universal asymmetry thresholds, such as <10 %, is not optimal. The regression model showed the relationship between asymmetries and COD performance. None of tests were sufficient to explain a complex variable like COD performance. Full article
(This article belongs to the Special Issue Sports Performance and Health)
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Open AccessArticle
Printability of the Screen-Printed Strain Sensor with Carbon Black/Silver Paste for Sensitive Wearable Electronics
Appl. Sci. 2020, 10(19), 6983; https://doi.org/10.3390/app10196983 - 06 Oct 2020
Viewed by 284
Abstract
Printing technology enables not only high-volume, multipurpose, low-impact, low-cost manufacturing, but also the introduction of flexible electronic devices, such as displays, actuators, and sensors, to a wide range of consumer markets. Consequently, in the past few decades, printed electronic products have attracted considerable [...] Read more.
Printing technology enables not only high-volume, multipurpose, low-impact, low-cost manufacturing, but also the introduction of flexible electronic devices, such as displays, actuators, and sensors, to a wide range of consumer markets. Consequently, in the past few decades, printed electronic products have attracted considerable interest. Although flexible printed electronic products are attracting increasing attention from the scientific and industrial communities, a systematic study on their sensing performance based on printability has not been reported so far. In this study, carbon black/Ag nanocomposites were utilized as pastes for a flexible wearable strain sensor. The effects of the rheological property of the pastes and the pattern dimensions of the printed electrodes on the sensor’s performance were investigated. Consequently, the printed sensor demonstrated a high gauge factor of 444.5 for an applied strain of 0.6% to 1.4% with a durability of 1000 cycles and a linearity of R2 = 0.9974. The sensor was also stable under tough environmental conditions. Full article
(This article belongs to the Special Issue Printed Function Sensors)
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Open AccessFeature PaperArticle
Green Extracts from Coffee Pulp and Their Application in the Development of Innovative Brews
Appl. Sci. 2020, 10(19), 6982; https://doi.org/10.3390/app10196982 - 06 Oct 2020
Viewed by 310
Abstract
Coffee pulp, a by-product of coffee production, contains valuable compounds such as caffeine and chlorogenic acid with high antiradical activity. In this study, aqueous solutions of β-cyclodextrin (β-CD) were used as a non-conventional solvent for the extraction of targeted compounds from coffee pulp. [...] Read more.
Coffee pulp, a by-product of coffee production, contains valuable compounds such as caffeine and chlorogenic acid with high antiradical activity. In this study, aqueous solutions of β-cyclodextrin (β-CD) were used as a non-conventional solvent for the extraction of targeted compounds from coffee pulp. The parameters of β-CD concentration (Cβcd), liquid-to-solid ratio (L/S), and temperature (T) were evaluated based on the antiradical activity (AAR) and the caffeine content (CCaf). The optimum operational conditions were found to be Cβcd: 9.25 mg/mL, L/S: 30 mL/g and T: 80 °C. The sensory profiles of brews prepared with coffee and coffee pulp with or without cyclodextrin were studied with quantitative descriptive analysis. The brew from the by-product had fruity, botanic, sweet and sourness sensory properties, and cyclodextrin was found to be able to affect the overall taste of the brew. Full article
(This article belongs to the Special Issue High-Performance Green Extraction of Natural Products)
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Open AccessReview
Integration of Molecular Docking and In Vitro Studies: A Powerful Approach for Drug Discovery in Breast Cancer
Appl. Sci. 2020, 10(19), 6981; https://doi.org/10.3390/app10196981 - 06 Oct 2020
Viewed by 212
Abstract
Molecular docking in the pharmaceutical industry is a powerful in silico approach for discovering novel therapies for unmet medical needs predicting drug–target interactions. It not only provides binding affinity between drugs and targets at the atomic level, but also elucidates the fundamental pharmacological [...] Read more.
Molecular docking in the pharmaceutical industry is a powerful in silico approach for discovering novel therapies for unmet medical needs predicting drug–target interactions. It not only provides binding affinity between drugs and targets at the atomic level, but also elucidates the fundamental pharmacological properties of specific drugs. The purpose of this review was to illustrate newer and emergent uses of docking when combined with in vitro techniques for drug discovery in metastatic breast cancer. We grouped the selected articles into five main categories; namely, systematic repositioning of drugs, natural drugs, new synthesized molecules, combinations of drugs, and drug latentiation. We focused on new promising drugs that have a good affinity with their targets, thus inducing a favorable biological response. This review suggests that the integration of molecular docking and in vitro studies can accelerate cancer drug discovery showing a good consistency of the results between the two approaches. Full article
(This article belongs to the Special Issue Anticancer Drugs Activity and Underlying Mechanisms)
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